Reviewing the 2014 xK% Overachievers, AKA: The Downsiders

Yesterday, I recapped my preseason starting pitcher strikeout rate upside target list using my xK% equation. So naturally today I’ll review the other side of that list, those pitchers who posted strikeout rates well below their xK% marks, which suggested potential downside for the 2015 season.

Jake Arrieta

2014 K% — 27.2%
2015 K% — 27.1%

Well hey, Arrieta’s strikeout rate did go down, amirite? In all seriousness, I’m fairly certain that 100% of the world figured Arrieta would suffer some performance regression across multiple metrics this year after his breakout campaign in 2014. Instead, his strikeout rate was nearly identical, he improved his walk rate even further, and his ground ball rate spiked for a second straight season. He’s undergone the amazing transformation from terrible pitcher to arguably one of the five (three?) best pitchers in baseball. Unbelievable.

Mike Fiers

2014 K% — 27.7%
2015 K% — 23.7%

Fiers was a trendy sleeper heading into the season and there were reasons to both like and dislike him this year. As suggested by xK%, his strikeout rate did tumble, though it remained well above average, and even coupled with an increased walk rate, he was still about to return solid fantasy value. He needs to make his changeup his primary off-speed offering, as it’s his only pitch that has generated a SwStk% above 10%. His fastball is good despite its low velocity, but his cutter and curve aren’t the whiff-inducers they should be.

Johnny Cueto

2014 K% — 25.2%
2015 K% — 20.3%

Coming off a season in which he outperformed his SIERA by nearly a full run, it was fairly obvious that Cueto was a candidate to be significantly overvalued in drafts heading into the season. Adding fuel to the fire was a strikeout rate spike that came out of nowhere and apparently wasn’t exactly backed by his underlying strike type peripherals. Sure enough, his strikeout rate fell back down to Earth and in line with his pre-2014 seasons, while his luck dried up. His BABIP reverted back to a normal range, as did his LOB%.

Corey Kluber

2014 K% — 28.3%
2015 K% — 27.7%

It hurt me to find Kluber in the overachiever category as I have been a big fan and a proud member of his namesake Society. Like Arrieta above, the right move is to always bet on regression after a big breakout, and while Kluber did technically regress, it certainly wasn’t to the degree xK% hinted was possible. It’s funny though how Kluber suddenly became less so-called “hittable” as his BABIP finally dropped to about league average, but since his LOB% declined as well, and HR/FB rate jumped to league average, his ERA jumped an entire run, despite similar underlying skills. He’ll be one of the better priced aces in 2016 drafts.

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So only four names here, a tiny sample size if there ever was one. Technically every one of them did see their strikeout rates drop, though only two really fit with the spirit of this list. Hopefully when I analyze xK% from this season, I’ll havemore than four names to discuss.