Big Baby ... I'll take an over-producing bench player over an injury-proned under-producer any day. Don't get me wrong, I love Perk when he's healthy, at least defensively, but the fact is, he's not healthy, and never stays healthy for long.
I disagree. Since Perk regularly got playing time, this is the first season he's ever missed more than 10 games due to injury. Since 2008, his games missed: 4, 6, 4.
Obviously, the knee is something to be monitored, but I definitely wouldn't call Perk injury-prone. He's had a fairly minor shoulder injury flare up a couple times, and now the knee issue. I don't think that's a troubling injury history for an NBA starter at all. Greg Oden is injury prone. Perk has had one major injury.
In terms of who to keep, I think the question comes down to health and contract. If the Celtics doctors are confident about Perk's prognosis, and if he shows himself capable of helping the team "win now", I think you have to keep him if he'll take a reasonable contract. Simply put, starting centers are less replaceable than bench power forwards.