Gotta be careful about using per 9 stats when part of your point is that he had a particularly good BABIP season. That means there's simply fewer PA in general, his K% was middle of the road for his career, and his HR/FB is impacted by playing most of his career in Coors. Since leaving Colorado he has 2 seasons and over 115 innings with an ERA far under his xFIP, given his stuff it's very possible that assuming a league average HR rate(like xFIP is doing) is not a safe assumption. ZiPS projects him for a 3.76 ERA and 3.73 FIP.