In an interview on 590 The Fan in Toronto, Colangelo said Bosh chose to sit out several games with an injury late in the season as the Raptors battled for the eighth seed in the Eastern Conference playoffs -- a race they lost by one game to the Chicago Bulls.
"Despite limited swelling and any excessive damage on an MRI, he felt like he needed to sit for six more games," Colangelo said on 590 The Fan on Monday.
"I'm not even questioning Chris' injury. I'm telling you he was cleared to play subject to tolerance on his part, and the tolerance just apparently wasn't there and he chose not to play."
The team's season was on the brink and the front office was hoping Bosh would return sooner to turn things around, Colangelo said. Now, he's not certain whether Bosh was thinking about the Raptors' playoff run or his own pending free agency.
"Whether he was mentally checked out or just wasn't quite into it down the stretch, he wasn't the same guy," Colangelo said. "I think everybody saw that, but no one wanted to acknowledge it."
Colangelo also said it was hard to build around Bosh as the team's franchise player.
"We tried in vain to put pieces around Chris. Different pieces, different styles. It didn't work out," he said. "No matter what type of player we brought in, it didn't seem to have the right mix with him as that centerpiece."