Yahoo's Adrian Wojnarowski reports that Smith sprained the patella ligament in his knee.
Atlanta's Josh Smith has sprained patella ligament in knee, source tells Y! "He walked out of arena w/ no help, just gingerly," source says.— Adrian Wojnarowski (@WojYahooNBA) May 2, 2012
The Hawks can ill-afford to lose Smith, especially given that the Celtics have gained home-court advantage with Tuesday's win. Smith appeared to injure his knee when he and Kevin Garnett battled for post position, as you can see here:
Smith left the game with 16 points, 12 rebounds and five assists in 36 minutes. Watch here as he leaves the game: