AaronGleeman.com

Back in early June, here is what I wrote in response to a Twitter mailbag question that asked, "Why does Ron Gardenhire stick with miserable Jesse Crain?":

Amusingly, that was sent in before Jesse Crain blew the lead Saturday.

Coming into Saturday's game he actually had a 3.32 ERA and 14-to-4 strikeout-to-walk ratio in 19 innings since back-to-back ugly outings in April, but that's the problem with Crain (and why people call him things like "miserable"). He tends to be awful, then pitch well for long enough to reclaim a prominent late-inning role, and then immediately be awful again. Crain also has a career xFIP of 4.55, including 4.34 this year, so he just isn't very good.

Since then Crain has thrown 28 innings with a 0.32 ERA and .136 opponents' batting average, which definitely qualifies as "pitch well for long enough to reclaim a prominent late-inning role." In fact, for the past month Crain's average appearance has been in higher-leverage situations than every reliever in the bullpen except closer Matt Capps. He's been unhittable for 10 weeks and Gardenhire is relying on him more and more as the primary setup man.

As for whether Crain will fall back into his aforementioned pattern and "immediately be awful again" following this success ... who knows. He's dominated before only to falter when trusted too much and while my statement that "he just isn't very good" looks awfully silly right now an amazing 28-inning run still leaves his xFIP at 4.07 this year and 4.49 for his career. However, his current stretch of success actually goes back much further than mid-June.

Crain struggled so much at the beginning of last year that the Twins demoted him to Triple-A in mid-June, but since returning in late July he's thrown 87.1 innings with a 2.78 ERA, 77-to-33 strikeout-to-walk ratio, .215 opponents' batting average, and just three homers allowed. That qualifies as extended dominance, and while I probably should know better by now I'm fully on board the "use Crain in the biggest spots" bandwagon.

As for how Crain is having this success, the answer is actually pretty simple. Despite a mid-90s fastball Crain's most effective pitch has always been his slider. Prior to this year he threw the slider 25 percent of the time while using his fastball 65 percent of the time. This season he's thrown the slider 46 percent of the time while using his fastball 43 percent of the time. So he's gone from throwing nearly three fastballs for every slider to using more sliders than fastballs.

And his slider, which has always been very, very good, has been downright extraordinary this season. According to Fan Graphs his slider has been worth 4.20 runs above average per 100 offerings, which makes it MLB's ninth-most effective pitch. His slider has been so untouchable and he's thrown it so often that it masks the fact that Crain's fastball has been far worse than usual at -2.20 runs per 100 offerings. His fastball has been terrible and he's still dominating.

That's one hell of a slider.