Golden State Warriors star Kevin Durant's rehab from an MCL sprain is going well, according to an update from the Warriors on Wednesday, and he could even return before the end of the regular season. But will Durant be 100 percent when he comes back?
Surely, Warriors fans have bad memories of Stephen Curry not being quite his usual self after suffering an MCL injury during the opening round of last year's playoffs. Curry shot just 40.3 percent from the field in the NBA Finals and had more turnovers than assists as Golden State lost to the Cleveland Cavaliers in seven games.
To get an idea of whether the lingering effects of Curry's MCL injury are typical, and what to expect from Durant, let's take a look at how other players have performed after returning from similar injuries.
Past Grade 2 MCL sprains
Technically, Durant's injury was actually more severe than Curry's. Durant's MCL sprain was diagnosed as a Grade 2 sprain, which is typically characterized by tearing of some but not all of the fibers in the knee's medial collateral ligament. (Grade 1 sprains like Curry suffered involve stretching or slight tearing, whereas a full tear of the ligament is categorized as Grade 3.)
Teams don't always disclose the severity of MCL sprains, but we can get a pretty good idea of which ones were Grade 2 from the timetable given after the diagnosis and how long the player actually misses. Grade 2 sprains usually sideline players five to eight weeks, whereas players can return from Grade 1 sprains within a week or two. (Curry played his first game 15 days after his injury.) Full tears of the MCL are rare and usually require more than eight weeks of recovery.
Using that criteria to expand on the list of Grade 2 tears compiled by Jeff Stotts of InStreetClothes.com in 2015, I found 28 such injuries dating back to 1994.
On average, these players went 46 days, or a little less than seven weeks, between suffering the injury and returning. (That timetable would put Durant back for the opening game of the playoffs.)
Performance before and after
Among that group of players, 15 played at least 250 minutes during the same season both before and after the injury, allowing us to compare their performance using Basketball-Reference.com's game logs. Here's how their average as a group changed.
For the most part, performance was unchanged or even improved after the MCL sprain. Players averaged a higher game score (a metric created by John Hollinger to measure single-game performance) per 36 minutes after returning than before the injury.
The only real area of apparent decline was in 3-point shooting, but this was counteracted by improvement inside the arc so that players' true shooting percentages were virtually unchanged. The sample sizes on the shooting stats get sliced pretty thin, and it's also possible that the apparent improvement in terms of game score is an effect of how offense tends to improve over the course of the season.
To better account for that effect and increase our sample size by including players who were injured early in the season or over the offseason, let's next compare how players performed after returning from an MCL sprain to what my SCHOENE projection system forecasted before the season based on performance the previous three years as well as age.
Performance vs. projections
Eight players get added to our sample if we require only that players see at least 250 minutes of action after their MCL sprain. (Three others returned too late in the regular season to get a reasonable gauge of post-injury play, and two more do not have SCHOENE projections because they did not play in the NBA the previous year.)
Here's how this larger group's performance after an MCL sprain compares with its SCHOENE projections.
Now, performance matches up to expectations even better, with players doing almost exactly as well after their injury as projected for the season -- with one interesting exception.
A drop-off in 3-point percentage is still apparent from this method, which might seem to explain why Curry struggled in last year's playoffs. His 40.2 percent 3-point shooting after returning was down from his 45.4 percent mark during the regular season, but Curry saw a greater decline in his 2-point percentage, from 56.6 percent during the regular season to 48.5 percent in the playoffs. That drop-off is atypical compared with players coming back from Grade 2 MCL sprains.
Curry's example should serve as a reminder that everybody will respond to injuries differently, and no two situations are the same. Still, it's encouraging to see how players returning from an MCL sprain have performed compared with their projections. Based on this track record, there's no reason we should expect Durant to come back from his injury diminished. The Warriors can feel comfortable knowing they'll probably have Durant playing at a high level when he returns.