The fact that you think his line drive rate in the past 20 games is more indicative of his true talent than the previous 10 years of his career is the confusing part. Line drive rate is just like anything else, it takes a while to stabilize.
This all said, I don't see the harm in giving the guy a shot. If he can wOBA something close to .300 with ok defense, he's a usable bench/depth piece.