The Colts roster is still in the making, Ballard does not have the luxury to let players go just because their market price is high or they are "old". If the Colts had a complete, deep roster, full with young, developing players who could step up and take the starting role, that would be a different story. But that's not the case. Ballard will need next years draft to address already existing needs: a premier pass rusher, a stud off ball LB, probably a (strong) safety, if Geathers neck won't recover. And then we will need another TE, an RB, a depth OL even if Mewhort stays, another CB even if Davis stays, etc. Thats already more than a full draft can provide.
So, assuming they will play well, I think all 3 guys will stay. Actually, I think there will be 1 or 2 of them, who will resign before the end of the season. That's what both sides are interested in. The player gets his contract, and the franchise can lock him up a bit below market price.