Portland center Jusuf Nurkic broke his right wrist during the Trail Blazers' 111-87 loss to the visiting Indiana Pacers on Thursday night.
Nurkic was injured with 8:29 left in the third quarter, falling to the floor after challenging a dunk attempt.
He finished the game with five points and eight rebounds in 21 minutes.
"It's very disappointing for him and for us," Trail Blazers coach Terry Stotts said postgame.
Nurkic missed most of the 2019-20 regular season after sustaining compound fractures to his left tibia and fibula in March 2019.
He returned to play in 13 games, including five in the postseason, during the NBA's summer restart after the season was paused due to the coronavirus pandemic.
"He had a long road back from his other injury," Stotts said. "He had a rough start of the season, it looked like he was getting back on track. Obviously this is a big setback for him and for us."
The 26-year-old Bosnia native is averaging 9.8 points and 7.7 rebounds per game this season.