This is the kind of low-risk, high-reward move the Brewers make all the time, and I wish the Rangers the best of luck with their Turnbow experiment. But I don't think you're going to see any sort of rejuvenation occur, because Turnbow is pretty much done.
An All-Star just a few years ago, few in baseball have fallen harder and faster than Derrick Turnbow. Once a fan favorite at Miller Park, he became public enemy number one due to his inconsistency and overall suckness.
He will be reunited with Mike Maddux, former pitching coach for the Brewers. But Maddux couldn't fix him last summer, and I don't see him doing it this time. Best of luck though.