We were 6 wins above our pythagorean expectation. I believe this to be because of the strong bullpen the team didn't let up runs when it really counted. Pythag is based solely on runs allowed and runs scored. B-R calls those six games "luck" but I call it a return from our investment...in a bullpen. We signed Broxton for quite a bit, but the Broxton that pitched for the Reds in '12 is worth that in todays game.
Like any big contract, and in this case, Chapman to the rotation, the proper evaluation of these moves can only be done in hindsight.