Last season MLB analysists were talking about Trevor Cahill as a Cy Young candidate for some strange reason. He only had a 2.2 WAR, hardly above replacement level. I assume they were in love with his 18 wins and 2.97 ERA. The thing is though, he isn't very good at all. Last year most of his success came from an absurdly low BABIP of .236, not sustainable at all. His 4.19 FIP indicated that he wasn't that good at all and his 3.99 xFIP tells us that his ERA will more likely be closer to that then his 2.97 ERA. His ERA- was 74 but his FIP- was 104 meaning his FIP was 4$ worse then league average. His xFIP was 95 though meaning it was 5% better then league average. He isn't a strikeout pitcher, only striking out 5.4 per 9 innings and walked 2.88 per 9.
Fast forward to this year and his .290 BABIP is a much more realistic number. His ERA is 3.92 so his xFIP last year was right on the money. His FIP is 3.98 and his xFIP is 3.80 so as we go on in the future I think this is the Cahill we can expect. This year Cahill's ERA- 103, his FIP- is 104 and his xFIP- is 96. These numbers just make it a little easier to see how his peripherals have caught up to him. This year he's increased his K/9 as well as his BB/9. He only has a 1.9 WAR and by the end of the season he shouldn't be too far off his 2.2 WAR of last season. He's striking out 6.61 per 9 but walking 3.7 per 9 which is slightly concerning.
In the end I think Oakland will regret giving Cahill the 5 year, $30.5 million dollar contract. From what we've seen he's pretty much a league average pitcher. He's only 23 but I believe they jumped the gun when offering the deal.