I don't know why a lot of people assume he's only had 1 good year. In his last 4 years he's actually only had one bad year which was 2014, in fact in 2012 he had a 3.3 fWAR season, far better than his 1.8 this year. He's been a consistent FIP beater during that time and has kept his BABIP far below league average throughout his career. Check out the article Gsnarles posted, it's a good read.