Perkins is not playing at 100% and his value is never in his stats.
Jeff Green is playing in a very limited role both in terms of minutes and touches.
For these playoffs, I feel reasonably confident that Jermaine, Shaq and Krstic can hold down the fort at Center.
Jeff Green can provide solid defense and scoring off the bench.
If you look at the trade, and fans hate this, it had A LOT to do with the future of the franchise. Ainge didn't like Rondo-Perkins long-term at a 40% share of the cap. I didn't either.
You also get trial period with Green with the possibility to resign for short (qualifiying offer) or small money (MLE type money, which was not even a remote possibility with Perkins.
Then you dump Robinson's dollars and add a potentially valuable first rounder.
Ainge made a gamble that J.O., Shaq and Krstic (and Jeff Green) could replace Perkins impact short term (largely because Perkins is not 100%) while strengthening the team long-term.
Regardless of how it turns out in these playoffs, I can live with the move.