Carter, taken by the Bulls with the No. 7 pick in last year's draft, was averaging 10.3 points, seven rebounds and 1.3 blocks. With high-IQ play and defensive potential, he had been a rare bright spot for the team in an otherwise dismal season.
The center out of Duke sprained the thumb last Tuesday in a game against the Los Angeles Lakers. The injury was not originally thought to be serious, and Carter said he expected to play the next game.
But an MRI on Friday revealed the diagnosis.
"I've laid it out for the guys that's how it's going to be," Boylen said. "I do like Bobby's energy and competitiveness off the bench. He can be a difficult matchup for a backup in the post and his ability to spread the floor. All those things kind of go into it. We'll make those decisions as we go.''
Carter's extended absence won't change the organization's direction on trade talks involving Lopez, ESPN's Adrian Wojnarowski reported on Friday. Lopez and his $14 million expiring contract will remain in the marketplace leading into the trade deadline.