This article was written about the 2005 NFL season and selected as a freelance article by Footballguys.com, but never published on the site.
Detailed Analysis of NFL Injury Reports for Fantasy Purposes
By ConstruxBoy
I. Introduction
One of the most difficult and frustrating experiences in playing fantasy football is checking the weekly injury reports and trying to decide whether or not your player will play in their game. Many a fantasy owner's ulcer has been started by coaches who do as much as possible to cloud their player's true injury status. I think it would help owners a great deal in their weekly start/bench decisions to examine how often injured players actually play and how much they contribute when they do play injured compared to their average fantasy output. I am going to attempt to shed some light on the injury report and how it can be used to its greatest utility by a fantasy football owner.
II. Parameters of the Study
Each week of the 2005 NFL season, I used the Footballguys Friday afternoon Injury Report in the Subscriber section. I entered every injury for every team to a starter at a normal fantasy football position (QB, RB, WR, TE, PK; apologies to IDP owners) for the three levels of injury status: Doubtful, Questionable and Probable. I skipped the Out status because there is never a reason to start a player who is declared out.
For each injured player, I recorded several different variables in the Raw Data section of the spreadsheet:
1) I recorded the week of the injury to see if there were any trends toward more injuries later in the year or more players playing through injuries later in the year.
2) I recorded whether the game is a non-Sunday afternoon game (Thursday, Friday, Saturday, Sunday Night, Monday Night) to see if less players play in earlier games or more play in later games.
3) I recorded the player's team to see if there were trends by team, such as Jeff Fisher not understanding the definition of the word "questionable".
4) I recorded the player's opponent and whether it was a division game or not to see if there were patterns of players playing more often in division games.
5) I recorded the player's position to see if there were any trends by position.
6) I checked the current depth chart to ensure that I was talking about "starters" when reporting and comparing this information.
7) I recorded the player's injury status to see if Probable players really do play more than Questionable players.
8) I recorded the actual injured body part to see there were any trends toward certain injuries, like the knee, making a player less likely to play.
9) After the game, I recorded whether the player played and how many fantasy points they scored on a 6/TD, .1 Rush/Rec Yds, .05 Pass Yds scale.
10) After the season, I recorded each players average fantasy points per game for the year and compared it to their points in the games they played hurt.
If it sounds like a lot of work, it was.
There are a couple of things worth clarifying with these parameters:
1) It is sometimes the case that a player may have their injury status change between Friday afternoon and game time, or that more information on a given player's chance of playing may come out on Sunday morning from an insider like Chris Mortensen. I did not account for these changes in this study.
2) To consider a player playing, I required them to score at least .1 fantasy points in the game. Obviously a player could see the field but never get a carry or catch a pass. However, tracking that through a play-by-play examination of each game is too difficult and the idea for our fantasy football purposes is that they contribute points.
3) Starters - I believe that the only accurate way to measure this information is to just track "starters", as backups are listed on injury reports but often don't play regardless of their injury. I used the Depth Chart to identify starters and keep in mind that it changes from week to week due to other injuries. Also keep in mind that I defined most WR3s, like Kevin Curtis, and RB2s, like TJ Duckett, as starters if they regularly receive work each game. So most teams will have 1 QB, 2 RB, 3 WR, 1 TE and 1 PK as starters. (One small exception was the week 15 Patriots, who listed their top 4 RBs as Questionable. Good luck figuring out the NE RB that week). This is obviously a judgment call on my part and will influence the results to a small degree.
III. Results
Overall
Now I would like to review some of the results on the study. The full data set and summarized results are available in the spreadsheet here. Overall, I tracked 562 injuries in which 374, or 66.5% (Play rate), end up with the player scoring fantasy points. The percentages based on the injury status were 5.6% playing for Doubtful, 50.4% playing for Questionable, and 89.7% playing for Probable. At a very high level, the lesson seems clear: Doubtful players seldom play and Probable players usually play. Baring any last minute game day updates, you should almost never start a Doubtful player and you should almost always start a Probable player. It's the Questionable players, appropriately, that need much further analysis.
Division Games
As you might suspect, the percentages of players playing in Divisional games is higher across the board, although not quite as high as I would have thought. The percentages are 7.1%, 56.9% and 90.6% for Doubtful, Questionable and Probable respectively. Although this wasn't originally part of the study, I calculated 562 fantasy position injuries for 256 total NFL games, or 2.2 injuries/game. I had suspected that the Divisional game rate would be higher in an attempt by some coaches at gamesmanship, listing more players as injured to throw off their most bitter opponents. This turned out to be true; 222 divisional fantasy position injuries in 96 divisional games for a 2.3 injuries/game rate. But the increase was not as high as I thought it would be. However, combining the higher injury rate for divisional games with the higher actual play rate for divisional games makes me believe that some gamesmanship is going on in these important contests. This is something to keep in mind when your player suddenly shows up on the injury list for an important divisional game.
Day of Game
Another part of the study was to examine whether players are more likely to play in later games (Sunday Night, Monday Night) or less likely to play in earlier games. With so many games on Sunday afternoons, the sample size for the other times are probably too small to be relevant. But the data does show an interesting result: Almost all the other game times (Thursday, Saturday, Sunday Night and Monday Night) show a higher overall percentage of players playing through the injury than Sunday afternoon, at play rates of 85.7%, 70.8%, 68.8% and 69.4% respectively to Sunday afternoon's 65.4%. Again the small sample size does skew the data some, but I would have expected a decrease for games before Sunday afternoon.
Week of the Season
Another way to examine the data is to see whether the players were more likely to play later in the season, when their team has completed its Bye week and might be fighting for a playoff spot. If you look at the week-by-week data in graphical form, you can't see any real pattern.
The only important trend that I see here is that week 17 shows a decrease in the percentage of Probable players who play, as well as a lower percentage in the Questionable category. This confirms the common knowledge that some players are rested in week 17 if their team has secured their playoff position.
What is a little bit more interesting is a graph of the total number of fantasy position injuries throughout the year.
Here you can see that the number of injuries grows throughout the season with a small dip down after the Bye weeks have been completed and then another upward trend leading into week 17. Players get more banged up as the year goes on, but this seems to be some further evidence that coaches increase their injury report as week 16 and 17 approach so that they can rest the starters.
Position
The positional analysis shows some interesting trends. First of all, the total percentage played results are as follows:
| QB | 80.5% |
| RB | 66.7% |
| WR | 63.0% |
| TE | 55.7% |
| PK | 74.3% |
I was not surprised to see QB and PK at the top of the list, but a little bit surprised to see TE at the bottom. Given that the TE is generally the biggest/strongest among the RB/WR/TE players, I expected them to play through injury more than most. When further examining the detail, I see that they have the second highest percentage of probable players who play, 92.6%, second only to the QBs' 98.1%. But they have an abysmal 41.3% of questionable players who play, almost 10% worse than the second lowest percentage, the RBs' 50.6%. The only explanation I can come up with for this anomaly, other than the fact that they really don't play through injury at the same rate as other positions, is that they are more replaceable in the lineup than the other positions. Maybe if the TE hurt was the blocking specialist, a team would change their game plan to adjust to using quicker patterns or more throws to the backup TE and not rush the starting TE back into the lineup. Looking at the raw data, many of the Questionable TEs who didn't play do appear to have been replaceable. Here is a partial list:
| Team | Questionable Starter | Possible backup |
| CLE | Aaron Shea | Steve Heiden |
| GB | Bubba Franks | David Martin |
| NE | Daniel Graham | Ben Watson |
| NO | Ernie Conwell | Zach Hilton |
| TEN | Erron Kinney | Ben Troupe |
| TEN | Ben Troupe | Erron Kinney |
So maybe in weeks 9 and 11 when Ben Troupe was questionable with an ankle injury, Jeff Fisher just changed the game plan to match Kinney's strengths. And when Kinney was questionable with a knee injury in weeks 15 and 17, Fisher worked Troupe's strengths into the game plan.
A lesson for fantasy football owners here may be that if your TE is questionable and there are other decent TEs on his team, it may be more likely that he does not play.
The position with the lowest percentage of Probable players to play was WR, with an 83.1% play rate. This is a lower percentage of probable players playing than the Overall Percentage, Division Percentage and most Week percentages. I am unsure of whether this means that the WRs cannot play as easily with a "probable" level injury as other positions or whether they just can't play through minor injury due to pain. I can see a minor injury affecting a WRs speed and making him less likely to be effective, although I can also see some of the "Prima Donna" WRs not wanting to play through the pain. For what it's worth, Terrell Owens was listed as probable 4 weeks and Randy Moss was listed as Probable 7 weeks and both played in every week.
Team
Some very interesting results are seen at the team level. Although there has been a lot of turnover in head coaches this season, there is still some value in seeing how coaches use the injury list. A common conclusion is that Jeff Fisher of the Titans never uses Probable or Doubtful but lists all his players as Questionable to make if more difficult for the other team to prepare.
To start the examination of the team-by-team results, I'll list the teams with at least 14 reported injuries and a less than 60% overall play rate:
| Team | # of Injuries Reported | Play Rate |
| NO | 14 | 28.6% |
| SF | 24 | 37.5% |
| CLE | 14 | 50% |
| GB | 16 | 50% |
| DET | 21 | 52.4% |
| JAC | 19 | 52.6% |
| HOU | 20 | 55% |
| CHI | 14 | 57.1% |
| STL | 24 | 58.3% |
| WAS | 22 | 59.1% |
Assuming that on average there was a 66.5% overall play rate, some of these percentages may help you identify teams that don't/won't let their players play through pain or risk further injuries. NO and SF are especially low. Jim Haslett has moved on from coaching the Saints, but Mike Nolan at SF does not appear to like his injured players to play.
Two interesting notes outside of this range: Both BUF and DAL only listed 3 fantasy position starter injuries all year, with the 1 Probable Bills player playing and none of the 3 Questionable Cowboys players playing. The teams may have just been lucky or possibly there coaches do not like to list players on the injury report. That is easy to see from Bill Parcells of the Cowboys based on his statements over the years, from Terry Glenn of a decade ago to Julius Jones recently.
At the other end of the spectrum are teams that have a high play rate. Here is a list of the teams with at least 14 players listed and more than an 80% overall play rate:
| Team | # of Injuries Reported | Play Rate |
| DEN | 14 | 92.9% |
| PHI | 25 | 92.7% |
| IND | 16 | 87.5% |
| CIN | 22 | 86.4% |
| CAR | 14 | 85.7% |
One interesting thing that I see from this data is that those are all some pretty good teams who have had a lot of recent success and have solid coaches. It seems that perhaps these coaches motivate their players to play through injury and that leads to more success on the field. On the other hand, maybe these good coaches like to list lots of players on the injury report even though they know that the player will be able to play. Either way, it's something to keep in mind for 2006.
Two interesting notes outside this range: The Giants were 100% on there 7 players listed and SD was 10 for 11 on their players listed. Both Tom Coughlin and Marty Schottenheimer seem like old school coaches that do not like to list many players on the injury report, but expect them to play when listed.
A more important view of the team injury results is checking each team's Questionable players to see if there are any trends that may help you when choosing who to start for your fantasy team. Here is a list of the Number and Play Rate for Questionable players on all teams:
| Team | # of Questionable Players | Play Rate | Team | # of Questionable Players | Play Rate |
| ARI | 2 | 50% | MIA | 7 | 71.4% |
| ATL | 6 | 33.3% | MIN | 2 | 100% |
| BAL | 4 | 25% | NE | 31 | 51.6% |
| BUF | 2 | 0% | NO | 14 | 28.6% |
| CAR | 4 | 75% | NYG | 3 | 100% |
| CHI | 7 | 42.9% | NYJ | 3 | 33.3% |
| CIN | 3 | 66.7% | OAK | 4 | 100% |
| CLE | 8 | 25% | PHI | 5 | 80% |
| DAL | 3 | 0% | PIT | 8 | 37.5% |
| DEN | 2 | 50% | SD | 10 | 90% |
| DET | 15 | 40% | SF | 12 | 33.3% |
| GB | 10 | 30% | SEA | 2 | 50% |
| HOU | 11 | 27.3% | STL | 6 | 50% |
| IND | 3 | 33.3% | TB | 9 | 66.7% |
| JAC | 6 | 16.7% | TEN | 44 | 72.7% |
| KC | 3 | 66.7% | WAS | 5 | 0% |
Some interesting notes from this list:
1) Jeff Fisher does win the award for most Questionable players with 44 and a 72.7% play rate shows that he is mostly just playing mind games. Bill Belichick comes in 2nd place with 31 Questionable players, but his players only play at a reasonable 51.6% rate.
2) Those 44 Questionable players are the only players on the TEN list. No fantasy position starter was ever listed as Doubtful or Probable. NO had the same oddity with a much lower play rate of 28.4%.
3) Although there were not many players listed, MIN, NYG and OAK get a thumb up for playing all of their Questionable players.
It's hard to draw a lot of conclusions from this data due to small sample sizes, but if nothing else it's instructive to see that most of the teams that list lots of players as Questionable, like NE, NO, DET, SF, HOU and GB, do not play those players at a very high rate. Other than the Patriots, those teams did not fare very well last season.
Injury
Finally, let's look at the Injury data to see if we can tell that certain injuries are less likely to result in the player playing in the game. First let's look at all the injuries with 15 or more instances and their overall play rate:
| Injury | Instances | Play Rate |
| Knee | 145 | 56.6% |
| Ankle | 70 | 60% |
| Shoulder | 56 | 75% |
| Calf | 35 | 80% |
| Foot | 34 | 79.4% |
| Hamstring | 31 | 67.7% |
| Back | 22 | 72.7% |
| Groin | 17 | 94.1% |
| Toe | 17 | 41.2% |
| Quad | 15 | 40% |
Two things that stand out from these numbers are the huge number of Knee injuries, with a poor play rate of 56.6%, and the very high play rate for Groin injuries. I would have expected Groin injuries to keep players out of the lineup more often.
Looking in more detail at the important Questionable listings, here are some of the good play rates for questionable injuries:
| Injury | Instances | Play Rate |
| Foot | 18 | 77.8% |
| Chest | 8 | 75% |
| Back | 14 | 71.4% |
| Elbow | 8 | 62.5% |
It seems like both Foot and Back injuries are pretty good bets to play, along with the Groin, based on the last two tables.
Now let's look at the poor play rates for Questionable listings:
| Injury | Instances | Play Rate |
| Quad | 7 | 14.3% |
| Knee | 72 | 37.5% |
| Concussion | 7 | 42.9% |
| Ankle | 42 | 45.2% |
| Hamstring | 13 | 46.2% |
| Shoulder | 21 | 47.6% |
So besides the already mentioned poor play rate on Knee injuries, it also looks like Quad and Concussion injuries are difficult to play through. Keep in mind, of course, that 7 instances of each of those Questionable injuries is a very small sample size.
Average points per Game
The secondary part of my research was to examine the number of fantasy points per game scored by players playing injured, compare that value to those player's average fantasy points for 2005, and see if there was a noticeable difference. It seems like the overall point per game average should be lower overall for injured players and likely lower as the injury status goes from Probable to Questionable to Doubtful.
However, looking at the actual data, this is only partially true. Here are the overall numbers:
| Injury Status | Avg Pts when Play | Avg Pts per Game for Year | Difference |
| Doubtful | 4.8 | 9.5 | -4.8 |
| Questionable | 9.2 | 9.4 | -0.2 |
| Probable | 11.1 | 11.3 | -0.2 |
| TOTAL | 10.4 | 10.6 | -0.2 |
The Doubtful values are based on only two players playing through injury (Randy Moss in week 7 and Fred Taylor in week 11), so the sample size is too small to draw a true conclusion. But look at the difference for Questionable, Probable and Total: Players who played only scored .2 points per game less than their yearly per game average. The value is so negligible that you could almost say that if a player plays through the injury, on average, they should score the same amount that they would any other week. I had expected at least a point or two difference for the Probable status and a couple of times that decrease for the Questionable status. Let's dig into more detail to see if we can identify situations where the players do score consistently less than their yearly average.
At the day of the week level, we still don't see any real statistical trend, although the game time with the largest increase in points scored versus average points scored was on Monday Night, the latest game of the week. But it was a mere .7 points per game above the average.
At the week of the season level, we do see an interesting trend if we graph the data:
Other than a small up tick in week 15, 4 of the last 5 weeks have negative values (with week 17 having the lowest value of the year), meaning the players who played hurt scored less than their average for the year. We could possibly conclude that as the year wears on, players who are playing through injury find it harder to perform at their highest level. This may be a consideration when starting an injured player near the end of the year.
At the position level there are no obvious insights. The only interesting piece of data was the fact that although TEs have the lowest play pct among positions at 55.7%, they have the highest average point difference with a 1.4 points a game increase from their yearly per game average when they do play. So you may have reason to be worried that your injured TE will actually play, but you probably shouldn't be worried that his fantasy points will drop off because of the injury.
At the team level there are a couple of small insights. The lowest average difference among teams with at least 5 players playing through injury are the -3.3 pts per game of SD and the -2.3 pts per game of MIA. My thought on this result is that maybe the coaches on these teams push their players to play through injury, even though the player really is too hurt to fully contribute. Although he is new to the NFL, Nick Saban seems like an old school coach that would press his players into action, as does the veteran coach Marty Schottenheimer. At the opposite end of the spectrum are the 3.4 pts per game increase of ATL and the 2.8 pts per game increase of DET. Possibly on these teams the players are only playing when they are truly at 100% and able to contribute as though they are not injured.
Finally, at the injury level there are some trends worth discussing. First of all, let's examine the overall average point difference for the injuries with 10 or more starts:
| Injury | Starts | Overall Avg Pts Diff |
| Knee | 82 | -0.3 |
| Shoulder | 42 | 1.0 |
| Ankle | 42 | -0.5 |
| Calf | 28 | 0.5 |
| Foot | 27 | -0.7 |
| Hamstring | 21 | -0.1 |
| Back | 16 | 1.7 |
| Groin | 16 | -1.2 |
One interesting note here is the Back injury, which we showed had a pretty high play rate, also has the highest average points difference here. You should feel more comfortable starting a player with a back injury than most other injuries. Conversely, the groin injury, which had a very high 94% play rate, has the lowest average points difference. So it seems like your player with a groin injury may gut it out, but not be very productive.
At the Questionable level, we also see two interesting trends. The average points difference for Questionable Knee injuries is -1.1 in 27 starts. The difference for Questionable Shoulder injuries is 1.7 in 10 starts. This reinforces the idea that knee injuries are difficult to play through and that shoulder injuries can be managed without losing too much production.
IV. Conclusions
One of my initial ideas for fantasy football use of this data was to string together the various play rates of a given injured player in 2006 to try to find out what the percentage chance was that they would play based on 2005 data. So for example, if I was trying to figure out whether to start the OAK RB in Week 6 in a non-Divisional game on a Monday night with a Questionable Back injury, I could average out the following:
| Detail | Play rate |
| Questionable - Overall | 50.4% |
| Questionable - MN | 57.1% |
| Questionable - Week 6 | 43.8% |
| Questionable - RB | 50.6% |
| Questionable - OAK | 100% |
| Questionable - Back | 71.4% |
| Total Average | 62.2% |
But now I think that a lot of the play rates included as equal weights in the average are going to be based on such small sample sizes that the result is not statistically relevant. However, it may still help someone to look through these play rates and make a generalization about whether or not their player will play. Looking at the above data, you could see the higher than overall rate for a Monday Night game and for a Back injury and maybe decide to start your player. The 100% play rate for Oakland looks nice, but Art Shell may do things totally different than Norv Turner did last year.
Although this study did not provide very many hard and fast rules that can be used to determine whether or not to start an injured player in your league, I hope that it helped point out some general trends in injury play rates and performance in those games. Some of the theories that I had regarding injury reports, such as certain coaches using the injury report as a "smokescreen" and Divisional games being an incentive to play through injury, were confirmed with this study. Others, such as games later in the week being easier to play in and injured players almost always scoring below their average, were not proven using this data set. However, hopefully you have gained enough insight into the trends in the injury report and it's use by the different teams to make your injury start/bench decisions easier and to help dominate your league.
