I hope not.
He will not. He knows that he has ONE MORE STAND next year with Rondo back.
Don't KG.

Roll your eyes all you want. This is a different team with Rondo on the floor. And I believe he knows that and he will play for one more year.
KG at worse can still patrol the defense and provide mid range shots to stretch the floor. If we get some help for him so he doesnt have to be the last line of defense, it will save his energy a lot.
A 37 year old Garnett is still better than a lot of PF's in the league. And he has one more year in the contract, he can just finish that up.
Rondo is coming back from a season ending ACL injury. That's not small. As intelligent as Rondo is, he still depends a LOT on his elite athleticism for his dominance. There is no guarantee at all that he will go back to being the dominante (at times) player he once was, and even if he does there's no telling how long it will take for him to shake off the rust. Could be old Rondo immediately (Chris Paul has come back from many an injury) but he could also go the Penny Hardway / Brandon Roy) route...you just don't know.
KG came back this season with all of this promise of a talented and deep roster, put himself through all of that grind again for another run. Put faith in the talent round him. Where did it get him though?
There has to be a point in time where a guy like KG eventually decides that as much as he loves to play, it's time to cut his losses and accept that he probably wont get another ring.
Last year he had just come off a deep run to the ECF after averaging 10/20 through the playoffs and giving a vintage KG performance in a season where his got by injury free. He would have had the fresh thought in his head of how close they were to one more ring, just 5 minutes away. Even despite this he still strongly contemplated retirement.
This year he's looking at a first round elimination in 4 games after struggling with injuries through what has been an up-and-down season. It's a much less promising, and there are far fewer amazing memories from this season to help inspire and motivate him.
I truly hope he does return, but I'm not confident given all that has happened this season.