The Fast Start

The first 30 innings pitched of Jeremy Hellickson's 2017 season couldn't have gone much better. He went 4-0 and despite posting just a 9.6% strikeout rate, his walk rate was also low (2.6%), and he was among the league leaders in ERA with a microscopic 1.80 mark. His 32.3% ground-ball rate and 46.9% fly-ball rate for had plenty of room for improvement, but he was doing what he could to minimize the damage by allowing hard contact just 25.3% of the time.

He was also pretty fortunate with regard to BABIP, as the .191 mark he put together was also among the league leaders. We -- along with many others, probably -- felt that negative regression was going to hit him pretty hard based on the huge difference between his ERA and SIERA, and boy, did it ever.

The Cold Streak

Those batted-ball stats we mentioned above didn't change very much, though his hard-hit rate did jump up to 31.3%. Hellickson has gone 1-4 over his last 8 starts (42 innings), which has also yielded an unsightly 6.43 ERA, but judging from what his April SIERA looked like (5.36), it's not much different from what he's done since that fast start (5.77 SIERA since May 1st).

What has changed drastically, though, is the rate of success opposing hitters are experiencing against the soft-tossing right-hander. The below table shows how Hellickson's wOBA and BABIP against have changed each month, along with his strikeout (K%) and walk rates (BB%).

The results have been very different, but the advanced stats show he's basically been the same kind of pitcher all year. The only real difference is that his good fortune didn't last very long.