I don't think he regrets it - mainly because there were more things to consider than just winning "right now". A few things that resonate for me about this trade:
1. There wa sno guarantee Perkins would stay healthy either. Even if he did stay healthy, there was no guarantee that that would mean we win #18 anyway...and pinning your championship hopes on an unathletic center coming off "major" reconstructive knee surgery isn't the best bet.
2. The fact of the matter is, we've taken a slide since our two "tough guys" in the middle went down. Jermaine is back, let's hope it's a minor set back for Shaq. If those two can give us 30-35 solid minutes a night between them - we'll most likely raise #18 this year.
But here's where the real motivation behind the trade comes - at least from my perspective - you have to ask yourself...
3. Does Kendrick Perkins fit in with the next team that Ainge will build around Rondo. That team will be a fast breaking, showtime type, major run and gun team. I'm not saying they won't play D, they will. But they are going to flying up and down the court. That is not a good fit for Rondo and for a fast break team.
4. Jeff Green is a good fit for that and that is in large part, why Ainge traded for him. Jeff Green fits in much better than Kendrick Perkins on the next team that Ainge "has officially already started building" with that trade.
5. Now, he made that trade and got a nice piece for the next team. BUT, he also saw that when Shaq and Jo were playing, the Celts were every bit as dominating as with perkins, if not more.
6. He also gets Nenad in the trade. No superstar - but not a bad 2nd or 3rd string center who gets up and down the floor better than Perkins. Green can get Pierce some rest, which is just as critical as getting oru big men back.
7. Let's look at a possible "next generation" team for the Celtics, built around Rondo.
Rondo / JGreen / DWest / Bradley / Nenad / Baby
That is not a bad Nucleus to build around. I don't think Ainge sees Green as a franchise player. I think he sees him as a 3rd or 4th option player. Ainge will be looking to add his next major superstar through free agency.
What if we could add Dwight Howard and maybe some other max free agent when KG and Ray are gone? We are basicallly re-built and Jeff green is a great complimentary piece.
No, I don't think Ainge regrets the trade. I think if anything, he might regrest letting Erden go for Murphy...Erden wouldn've been a nice young piece at center.
Finally, given just decent luck with health, we'd have Shaq, Jo, Krstic, and just as good a chance at a title, plus Green for the future...