Pitchers who pitch to contact as Detwiler does tend to outperform their FIP and xFIP. Detwiler would not be the first pitcher to consistently outperform his sabermetric numbers. Again, sabermetrics are great but they aren't perfect for every pitcher.
That's fine. But it means he must depend upon solid defense to help him out (which the Nats do have currently). And what happens if he can't maintain his ridiculous groundball rate? There's nothing wrong with pitching to contact and there are plenty of pitchers who have been very successful with that approach but there are reasons why sabermetrics prefers high strikeout/low walk guys.
