Jhonny Peralta is not a great player, but he is a major league regular.
And he is better than the Tigers have been putting on the field in most cases, and will give them a better chance to win some games and remain in contention.
He does have 43 RBI this season and has played in pressure games before. Don't forget how good the Indians were in 2007. And the Tigers didn't give up much to acquire him. But the Tigers still, in my opinion, need to make another move for an outfielder. They need another outfield/DH bat. Doesn't look like Brennan Boesch is going to come out of this tailspin any time soon.