Horford would have to be a rental. It'd be irresponsible to re-sign him for five years at the new max, not to mention unlikely he'd even want to.
Don't agree Dino.
I think if Ainge could convince Horford to help him bring a premium FA to Boston this summer, he'd agree to give him the full 5 year max in exchange -- something no other team can do if he's traded here this season.
Is it overpaying? Sure. But if it achieves the end goal of actually signing two top tier guys and competing for a championship -- who cares? Wyc will make that money back in spades, and Ainge has managed the cap beautifully with other portions of the roster, plus a variety of nice picks to ensure rookie-scale players going forward.
Ainge waits for his moments to take risk, but he understands you have to to create a real shot. And having Horford onboard would make Boston is a REALLY attractive destination, when you factor all other elements.
Sigh. You're probably right. It would probably wind up being a massive overpay in the 4th and 5th years, but if that means winning over Durant* and having a championship window in the 1st, 2nd, and 3rd years then it'd be worth it. Besides, that 5th year he'd be an expiring contract at worst and could be moved along with whatever asset surplus Ainge has rebuilt by then for another star. And hey, there's a chance he'd be worth his contract (or close enough) all five years. He's not guaranteed to fall off a cliff. Alright, I'm talked into Horford long term...Let's be irresponsible and win a championship!
*Aside from Durant and Horford, there are no other premium free agents this summer who'll be changing teams. Horford would still make the Celtics a more attractive destination for the next tiers of free agent talent, as well as disgruntled stars who have a say in where they get traded.