All-Star forward LaMarcus Aldridge has a hip flexor strain and is day-to-day.
The 6-foot-11 Aldridge sustained the injury during Wednesday night's practice and did not participate in practice on Thursday. His return is uncertain.
The Blazers opened training camp on Tuesday in preparation for the coming season.
Aldridge, a seven-year NBA veteran who was named an All-Star for the second straight year, averaged 21.1 points and 9.1 rebounds per game last season.
The Blazers also say guard Will Barton sustained a concussion.