That's Michael Pineda's slider plot from last night. He threw that pitch 39 times out of 92 total pitches, by far the most of any of his offerings, despite not having very good command of it. Miguel Sano took him deep on a hanging 3-2 slider to get the Twins' offensive outburst started and they put a lot of good swings on other sliders that missed up in the zone. Normally the slider is Pineda's best pitch and one he uses to rack up strikeouts. Last night the Twins put it in play 25.6% of the time they saw it and did a lot of damage against it.
Location in the strike zone is usually the issue when Pineda's slider isn't working and last night was a prime example of this. Throwing almost 75% of 39 sliders inside the zone is way too many for what is supposed to be a swing-and-miss out pitch. Throwing at least half of that 75% up and in the middle of the zone is real good evidence of Pineda not having the feel for the pitch, as is the location of most of the sliders he did manage to bury down out of the zone. That pitch is supposed to drop down and away from right-handed hitters towards the bottom quarter of the zone and beyond. That wasn't the case last night, as more often than not the pitch floated over the middle third of the plate and didn't have the sharp late break it usually does.
Whatever the cause last night - mechanics, fatigue, just an off-night - Pineda's struggles with slider command has been a reoccurring theme over these past few months of uneven performance. He isn't the same pitcher without that swing-and-miss slider, and it's clear that he hasn't developed his changeup enough to be reliable and effective without the slider. I'm sure Roth has something in mind to work on with Pineda to fix this and hopefully it's a fix that lasts longer than a start or 2. The Yankee rotation is much less scary when he's scuffling.