I came here to post exactly this. I stated pretty clearly that Wacha's performance is very fielding dependent, no matter the sample. This is, at best, an average defensive team that needs IP more than anything else. Also, and I've said this before, 200 K starters don't grow on trees. If there's an anomaly to Giolito's performance, it's giving up 40 bombs. Any type of regression model you use has Giolito being better this year than he was last year, and almost certainly more valuable than Michael "Owie, missed another month" Wacha.