If you want to know why the Portland Trail Blazers have exceeded expectations during a season that is likely to result in their first playoff trip since 2011, start in the training room. There should be room to look around, because it's been relatively empty this season. Four of the Blazers' five starters have played in all 75 games this season, and as a team, Portland ranks in the league's top five in fewest games, minutes and WARP lost to injury.
The Blazers aren't alone in parlaying good health into exceeding expectations. The Toronto Raptors have been healthier than any other team in the league en route to a near certain Atlantic Division championship, while the Indiana Pacers have stayed healthy as part of their challenge for the top seed in the Eastern Conference postseason.
Looking beyond those examples, leaguewide numbers confirm the importance of health to making or breaking a season in the NBA.
More injuries, fewer wins
Using data through last week from my injury database, which includes games missed due to injury or illness but not suspension or personal reasons, there's a minus-.46 correlation between how many games a team has lost and its winning percentage this season. That means there is a relationship between injuries and results on the court, with more injuries translating into fewer wins.
On average, the 10 healthiest teams in terms of games missed have won 56.3 percent of their games. The bottom 10 have been even worse, winning just 41.8 percent of the time. That's equivalent to a 12-win swing over a full season between being among the 10 healthiest teams and the 10 most injured, though the fact that injuries are more predictive at the bottom points to an issue with the data.
When it comes to injuries and losing, the causation runs both directions. While teams with more injuries are obviously more likely to struggle, it's also true that teams eliminated from the playoffs tend to see their injury rates rise. Sitting players with questionable health can be a subtle form of tanking, though it's also pragmatic. With nothing tangible left to play for, there's little justification for risking reinjury.
Looking at individual teams makes it easier to see how health leads to success or failure.
Seasons ruined by injuries
Among the six teams that have lost the most games to injuries, only the Golden State Warriors are headed to the postseason. And most of the Warriors' injuries have been to reserves like center Festus Ezeli, who has missed the entire season after knee surgery. Golden State doesn't rank in the top 10 in minutes lost (based on minutes per game injured players saw when available) and has actually lost fewer WARP (based on my wins above replacement player statistic) than average.
Most of the teams at the bottom, including the lowly Milwaukee Bucks and Philadelphia 76ers, were unlikely to be competitive even if healthy. But the Denver Nuggets and New Orleans Pelicans hoped to compete for playoff spots in the Western Conference, and while they would have had a tough time keeping up with tough competition in the West, both saw those plans scuttled by injury. The Pelicans have lost more player wins to injury than any other team in the NBA, while Nuggets star Danilo Gallinari hasn't played all year. He's one of three Denver players who have undergone ACL surgery.
Of course, it is possible to overcome injuries. The Brooklyn Nets have done a better job of that than perhaps anyone else in the league. The Nets rank 20th in games lost but 29th in WARP lost because their injuries have tended to strike key players -- notably center Brook Lopez, who was ruled out for the season after 17 games.
Because Andrei Kirilenko, Paul Pierce and Deron Williams also missed extended stretches early in the year, Brooklyn had no lineup play more than 121 minutes before the All-Star break, per NBA.com/Stats. That instability made continuity hard to find. Since the break, despite having Kevin Garnett out of the lineup, Jason Kidd has been able to settle on a starting five and rotation to help fuel the Nets' rise.
Healthy results
By contrast to Brooklyn, the teams with exceptional health have been able to keep their starting lineups intact much of the season. Indiana's starting five has played a league-high 1,379 minutes together, per NBA.com/Stats, with Portland's starters next at 1,251 minutes. The Minnesota Timberwolves' starting five is the only other unit to play at least a thousand minutes together. The Raptors' quintet comes in sixth at 682 minutes but moves up to third behind the Pacers and Blazers since the midseason trade that sent starter Rudy Gay to Sacramento.
Recent slumps for Indiana and Portland can be traced to some extent to that continuity being interrupted. The Pacers' starting lineup has remained intact, but the team has missed backup point guard C.J. Watson. Indiana was 5-9 in the 14 games Watson missed in March due to a sprained elbow ligament and a hamstring strain and was outscored by 21.4 points per 100 possessions during the 151 minutes third-string point guard Donald Sloan played in that span.
After running out the same starting lineup for every game before the All-Star break -- tied for the sixth-longest streak in NBA history -- the Blazers have been forced to adjust as LaMarcus Aldridge has battled injuries since then. Aldridge's absence has been compounded by the loss of their top reserve in the frontcourt, Joel Freeland, to a sprained MCL. While Portland is 7-5 overall without Aldridge, it lost the last three games he missed last week before returning just in time to spark a three-game winning streak.
The relationship between health and winning isn't always that black and white, but it's real and important to determining where teams finish.