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One of the dominant storylines of the first month of this lockout-shortened season has been injuries. From Al Horford to Derrick Rose, from Chris Paul to Eric Gordon, from Dwyane Wade to Manu Ginobili, from Zach Randolph to Andrea Bargnani, a number of key players have battled ailments It's easy to see how a compressed schedule and a brief training camp would translate into more injuries.
At the same time, I'm always skeptical of such convenient storylines--especially in the case of injuries. Minor knocks tend to seem important at the time, but ultimately fade. For example, besides Oklahoma City fans, who remembers the sprained ankle that kept Kevin Durant out for two games last November? I also suspect that because injuries are such a soft issue--not easily quantified--it's easy to misremember how often they actually occur. In economic terms, we don't have a good understanding of the base rate of injuries. Because good health is the default assumption, we can think of injuries as anomalies rather than an inherent part of the sport.
To try to get a better understanding of the issue, I updated the injury database volunteers Dirk van Duym and Joe Dombrowski helped me compile over the summer. Using media notes and other sources, I added all injuries through Monday--120 of them in all, up from 107 through the same portion of the 2010-11 season. (Unfortunately, the data is less reliable the further we go back, so I did not use 2009-10.) However, the schedule is obviously to blame on one level. There have been far more games during the first three-plus weeks than there were last year: 194 vs. 166. Accounting for that, injuries per game are actually down slightly from 0.64 to 0.62.
Case closed? Not quite. You see, I also have data on when the injuries occurred, and there's an enormous difference between the two seasons. In 2010-11, 45 players were sidelined before opening night--either preexisting injuries or those suffered in training camp. This year, that number was down to just 29. It's logical that, with just two preseason games and barely two weeks' worth of practices, fewer players were injured prior to the start of the regular season this time around. Take out those injuries and it becomes clear that far more players have been injured during the first three weeks' worth of games:
Year Injuries Camp Season Seas/Gm
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2011 107 45 62 0.47
2012 120 29 91 0.37
Total injuries suffered during the regular season are up nearly 50 percent, a discrepancy that cannot be explained away by the increased number of games. On a per-game basis, in-season injuries are up more than a quarter.
There doesn't appear to be any particular pattern in terms of severity. By this time last year, more players had already suffered season-ending injuries (six) than apparently have so far this year (five, counting torn pectoral muscles suffered by Horford and Kwame Brown, who might be able to return). But neither are there more of the day-to-day injuries, which I suspected might be more difficult to play through given the number of back-to-backs on the schedule.
The average number of games missed per injury was higher in 2010-11, but this can be explained by the number of preseason injuries that had already run their course--we still don't know how long some players will be out this season.
Most injuries are too infrequent to tell whether they are happening more often this season or not. However, one type of ailment worth keeping an eye on is players missing games due to soreness, which encompasses a variety of different injuries. Soreness was mentioned in 13 injuries through the first three-plus weeks last season and is up to 18 so far this year. Soreness is exactly the kind of wear-and-tear injury that we would expect to see more of with a compressed schedule.
For now, studying the numbers on injuries leaves us with as many questions as answers. The rise in injuries since the start of the regular season could be a blip, or it could be a sign of things to come as fatigue becomes a larger issue later in the campaign. Since everyone will be paying close attention to injuries throughout the season, we'll continue to check the numbers.
Lastly, here's a look at injuries on a team-by-team basis using the measures introduced in last season's analysis to estimate minutes and WARP lost in addition to simply games missed due to injury. Because this year's stats have yet to shake out, the WARP numbers are a little off at this point. (Corey Maggette's, for example, rates as a huge positive for Charlotte.) For players who have yet to play this season, I used last 2010-11 numbers, except in the case of two injured rookies yet to debut (Malcolm Lee and Ryan Reid) and Greg Oden, who were zeroed out.
You'll note that two of this season's biggest surprises--Philadelphia and Utah--have benefited from uncommonly good health thus far. The Timberwolves, by contrast, have frequently played with just 10 healthy players because of their series of injuries.
Team GM Rk Min Rk WARP Rk
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MIN 60 30 924 29 0.3 16
CHA 44 29 906 27 -0.9 1
TOR 38 28 591 24 -0.2 4
NOH 35 27 977 30 0.4 21
NYK 32 26 806 26 0.9 26
NJN 31 25 907 28 0.4 20
LAL 26 24 311 15 -0.1 6
MEM 25 23 553 22 0.8 25
MIL 24 22 569 23 0.0 7
ATL 23 21 644 25 1.0 28
Team GM Rk Min Rk WARP Rk
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WAS 22 20 353 17 -0.3 3
CHI 21 18 488 21 0.8 24
LAC 21 18 483 20 0.5 22
GSW 16 15 421 19 1.3 29
MIA 16 15 388 18 0.9 27
SAS 16 15 329 16 1.6 30
POR 15 14 46 1 0.1 9
IND 14 13 180 11 0.4 19
OKC 13 12 112 6 0.0 8
BOS 12 9 224 12 0.3 15
Team GM Rk Min Rk WARP Rk
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DET 12 9 146 10 0.1 12
HOU 12 9 292 14 0.6 23
SAC 9 8 259 13 0.1 11
CLE 7 6 93 5 -0.5 2
DEN 7 6 137 9 0.3 17
ORL 6 5 113 7 -0.1 5
DAL 4 4 114 8 0.3 18
UTA 3 3 62 4 0.1 13
PHI 2 1 53 2 0.2 14
PHX 2 1 55 3 0.1 10
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Kevin Pelton is an author of Basketball Prospectus.
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Prospectus Diagnosis (01/18)
4 comments have been left for this article. 
Great idea to adjust for camp vs. non/camp injuries. I wouldn't have thought of that.
I think the games lost and WARP lost would naturally skew higher this year because of the greater frequency of games, even if there were not 25% more injuries per game. A sprained ankle will still take 2 weeks to heal, but if a player misses 8 games in that span this year instead of 6 it only exacerbates the issue.
So it would seem the problem this year may be twofold: There could be more injuries on a per game basis, and those injuries hurt the teams more because the player misses more games.
Yep. Very true.