Stars more injury-prone than ever
— -- Let's start with the conclusion and work backward. Injuries aren't up in the NBA this season, but there's a good reason it feels like they are.
From Paul George's horrific fibula/tibia fracture during last summer's USA Basketball training camp to reigning MVP Kevin Durant likely being ruled out for the season last week, the 2014-15 NBA campaign feels like it's been dominated by injuries. Yet the injury data I've tracked suggests the rate at which players have missed games due to injury is fairly typical. The disconnect can be explained in part by more injuries striking star players than usual.
Injury Rates, Season by Season
To measure the impact of injuries in the NBA, I've been tracking them for the last six seasons. Over that span, on average about 3.7 players combined among the two teams have missed each game due to injury. This year's rate, so far, is ... 3.7 players absent for each game.
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That number is actually down slightly from last season, when the average of four players out with injuries for each game was the high-water mark over the last six years. Because injuries tend to accumulate over the course of the season -- a natural tendency exaggerated by teams out of the playoff race acting conservatively with their injured players late in the year -- the rate might creep up slightly over the remainder of the schedule. However, it's unlikely 2014-15 will surpass 2010-11 or the lockout-shortened 2011-12 seasons, when an average of 3.8 players missed each game.
It's difficult to compare recent injuries to the historical trend in the NBA. My database doesn't extend past the last six seasons, and even if it did any data before 2005-06 would be tough to interpret. That's when the league moved to an inactive list rather than an injured list, which forced teams to come up with bogus or at least exaggerated injuries to keep extra players on their rosters.
More Injuries to Bigger Names
Digging deeper into the data reveals an interesting trend. While the rate of injuries doesn't seem to have changed much over the past six seasons, the amount of minutes and wins lost to injury has gone up. I estimate those totals based on minutes per game injured players average when healthy, and their average wins above replacement player (WARP) per game by my rating system.
This season has featured the most WARP lost due to injuries per game of any season in my database, while minutes lost have been above 80 per game three of the last four years after being well below 80 the first two on record. Taken together, the data suggests that injuries have disproportionately affected better players the last few seasons as compared to the first two in my database.
That's consistent with the subjective quality of the names on the injury list. Besides Durant and George, Carmelo Anthony, Kobe Bryant, Chris Bosh and Dwight Howard are among the All-Stars who have been sidelined for extended periods. The MVP race has been significantly affected by health. In addition to ruining Durant's chances of repeating, injuries to Anthony Davis, LeBron James and Russell Westbrook have hurt their cases for MVP.
To put the injuries to stars into a historical context, I looked back at All-Star teams dating back to 1978, finding what percentage of games All-Stars have played the following season. The trend is fascinating.
Before 2010-11, All-Stars had collectively missed more than 20 percent of their games the following season just twice, 1997 All-Stars in 1997-98 and 2004 All-Stars in 2004-05. Remarkably, that's happened each of the last four years. Last season actually featured the worst health by incumbent All-Stars, who collectively missed nearly a quarter of their games due to extended injuries suffered by Bryant (limited to six games), Brook Lopez (17), Rajon Rondo (30) Jrue Holiday (34) and Westbrook (46).
It's too early to draw any conclusions from this trend, but it certainly has to trouble the league. As entertaining as the 2014-15 season has been, it could be even better with something closer to full participation from star players.
