He's no Hall of Famer, but in 2013 he finished 28th in the NL in ERA+. Back-of-the-envelope, that's about two pitchers per team like that. It was a typical season for him - 2012 was a bit better, 2011 was worse. It's not easy to be 100 ERA+ as a fulltime starter, year in and year out. If he's not "good", it's going to be extremely difficult to acquire someone who is.