NBA: No structural damage to Duncan's sore knee

San Antonio Spurs forward Tim Duncan underwent an MRI exam on Sunday that showed no structural damage on his sore left knee a day after he was injured in an NBA victory over Washington.

Duncan, who is averaging 17.3 points and a team-high 9.7 rebounds for the Spurs, had missed four games in a row with a knee injury before returning to the court in San Antonio's 96-86 home triumph.

But in the second quarter of the contest, Duncan suffered the knee injury as well as a mild sprain of his right ankle.

At 38-11, the Spurs have the best record in the league just ahead of Oklahoma City, 35-12.

Duncan, the NBA Rookie of the year in the 1997-98 season, sparked the Spurs to NBA titles in 1999, 2003, 2005 and 2007. Only Boston, Chicago and the Los Angeles Lakers have won more crowns than San Antonio.