Oklahoma City Thunder guard Andre Roberson is expected to miss the rest of the season after he ruptured his left patellar tendon.
The Thunder made the announcement in a news release on Sunday and said the injury will require surgery.
Thunder coach Billy Donovan said it will be difficult to fill the void left by one of the league's top perimeter defenders.
"You don't replace him," Donovan said. "It's no different than having a guy that gets 25 points a game and goes out. You're not going to have one person go out and replace 25 points."
Roberson was taken off on a stretcher in the third quarter of Saturday's game at the Detroit Pistons after landing hard on the court. His left leg seemed to give way as he was beginning to jump for an alley-oop, and he landed on his tailbone or lower back.
The 6-foot-7 Roberson was an All-Defense second-team selection last season. In 39 games this season, he averaged 5.0 points, 4.7 rebounds, 1.2 assists and 1.15. He had missed eight games earlier in the season with left patellar tendinitis.
Roberson's absence will also make it difficult for All-Star Paul George, also considered one of the best perimeter defenders in the league, to gamble for steals. George is second in the league in that category.
Donovan said George's role won't change.
"The one thing that I think is a mistake is now to throw all this onus on Paul George, that he now has to be our defensive stopper," Donovan said. "It has to be our team."
Donovan said rookie Terrance Ferguson would start Sunday against Philadelphia, but he did not guarantee Ferguson would remain the starter going forward. He said the slot would be filled by the player who makes the most sense on a game-by-game basis.
"It's not about, `Hey, listen, you've got to prove to me to earn the spot,"' Donovan said. "I trust Terrance. Terrance is a terrific player, he's a great guy, he's a team guy, he's unselfish. He'll do anything that's asked of him."
Wade might be back Tuesday
Cavaliers coach Tyronn Lue expects Dwyane Wade will return Tuesday for Cleveland's game at Detroit.
Wade was excused from the team following the death of his longtime agent Henry Thomas. The veteran guard missed Friday's victory over Indiana and won't play Sunday against the Pistons.
Wade is averaging 11.1 points, 3.9 points and 3.7 assists in 42 games. The 36-year-old guard started the first three games of the season, but has been a key player off the bench since.