Portland Trail Blazers center Deandre Ayton underwent an MRI on Tuesday that revealed a left calf strain, the Blazers announced Wednesday.
Ayton had already been ruled out for Wednesday night's game at Denver.
Ayton left Monday night's 146-117 loss at the Nuggets in the third quarter after injuring his calf.
The injury came with the Blazers losing two consecutive games after winning 10 of 11 to get back into the race for a play-in berth in the Western Conference.
The Blazers entered Wednesday 4½ games out of 10th. Losing Ayton will likely lead to rookie Donovan Clingan taking over as the starter. Robert Williams III is questionable for Wednesday with right knee soreness.
Clingan has played well in stretches but has yet to demonstrate he can log starter-level minutes for an extended period of time.
Blazers point guard Scoot Henderson left Monday's game with a right ankle injury. He is out for Wednesday and will not play in Friday night's Rising Stars tournament during All-Star weekend.