Jeremy Hellickson may be the closest thing to Dr. Jekyll and Mr. Hyde on the current Rays roster. I don't mean that in the sense that Dr. Jekyll shows up to pitch one day and has a stellar performance and then Mr. Hyde comes out five days later and has a disastrous start. Hellickson has been quite steady, actually. I am talking more in the stat columns. Let me explain.
Both the casual fan and the fantasy baseball fan will look at his stats and say he could be the mild mannered Dr. Jekyll. He sports a nice 3.21 ERA, 1.15 WHIP, has 8 wins, 9 quality starts, and goes deep into almost every one of his starts, having yet to go less than 5 complete innings.
The sabermetric fan will look at Hellickson and see the monster that is Mr. Hyde. His 4.32 FIP is 13% worse than the league average and 19th worst among all MLB pitchers with at least 100 innings pitched and his xFIP is even worse at 4.48. The 5.90 K/9 and 3.39 BB/9 are far and away the worse rates he has had in his professional career, and his BABIP of .224 would support the theory that he has been very lucky this season.
Tommy Rancel did a good study on Hellickson's BABIP and the conclusion I drew from it was that his BABIP may actually be a somewhat sustainable and largely thanks to his skill. If this is true then his true performance may be closer to his ERA than his FIP. But it still does not explain the low strike out rates and higher walk rates. After all, his swinging strike percentage is a healthy 10.2%. So why are his rates so out of whack?
I honestly hate to blame someone else for the failures of another but in the story of Dr. Jekyll and Mr. Hyde a potion had to be taken to transform Dr. Jekyll into Mr. Hyde. In Hellickson's case the potion that is turning him from Dr. Jekyll to Mr. Hyde may be the umpire's strike zone against him. Thanks to Pitch F/X we can take a look at his called strike zone plot and how many pitches in the zone have been called balls and how many other borderline pitches have not gone Hellickson's way:
I went ahead and looked at other pitchers like Jair Jurrjens, Roy Halladay, and even our very own staff and no one has been pinched the way Hellickson has. If Hellickson could actually get the pitches in the zone called for strikes and add that to his good swinging strike rate then I think we will see the Mr. Hyde act disappear.