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What happened to Jakob Junis?

The promising young pitcher has struggled recently.

MLB: Houston Astros at Kansas City Royals Peter G. Aiken

It’s hard to believe, but April was a simpler time when analyzing the Kansas City Royals. Everything was new, there weren’t any nine game losing streaks, and most importantly, there was still hope.

Jump forward a few months and not only has the train veered off the tracks, but the train has come to a grinding halt, the doors have fallen off and someone decide to light it on fire. In other words, things aren’t going great.

In fact, some of the players who appeared to be glimmers of hope have now lost their shine. That includes the performance over the last month of Jakob Junis. I actually had taken a deeper look at Junis back in April when hope was still a thing. He was shoving throughout the month and it appeared that he was well on his way to proving his worth in the Kansas City rotation.

But the times have changed and Jake has run into a bit of a rough patch. So far in the month of June (which consists of four starts), Junis has thrown 24 innings, allowed 18 runs while posting an ERA of 6.75. The numbers don’t get any better from there: batters are hitting .289/.346/.526 against him this month with seven home runs allowed and a WPA of -0.685. So how did we go from an April where the league was hitting .181/.244/.422 against this?

Let’s start with his pitch usage and if there is a notable change:

There are a few noticeable things here, like the increase in using his change-up and a decrease in his four-seamer. But what is more concerning is how the use of his slider (his main weapon) has gone down this past month. Maybe the bigger question to ask here is how are hitters performing against these pitches. First, here’s batting average against:

So ignore the insane increase in average on the curveball; Junis has only thrown one curve this month. The most concerning part here appears to be the sinker, which in April was helping his cause. Batters hit .219 on the sinker in the first month of the season, compared to .440 now. Obviously it is not having the same affects.

The good news is the slider is still doing its job, as batters are only hitting a paltry .132 against it. Now let’s move to slugging percentage:

Once again, ignore the curve. The two biggest upticks in slugging percentage appear to be on the four-seam and the sinker. We already established that the sinker wasn’t having the same success it did earlier in the season, and it appears the four-seam is getting hammered, as evidenced by the .846 slugging percentage against. These numbers are backed up by the isolated power numbers:

This shows that hitters are getting a number of their extra base hits off of Junis’ four-seam fastball and the sinker has seen an almost 100 point increase since April (.188 to .280). One encouraging sign here is the value of his slider, as it continues its two month slide (pun intended). Back in April, there was a .204 ISO against his slide-piece while in June it sits at a robust .079.

One answer might be in the vertical location of his pitches:

The chart shows an increase up in the zone with both the four-seam and the sinker. While there are times a fastball up in the zone is a plus, if it catches too much of the zone it can be a problem, which appears to be the case here with Junis.

Finally, one last chart to drive home the lack of productivity from these two pitches:

There has been a noticeable increase in the percentage of grooved four-seamers and sinkers, while his other pitches have seen a decline. In fact, his slider has gone down from 7.36% last month to 3. 25% in June.

So more than anything, it appears the fastball and sinker are the cause for most of the ills for Junis over the last couple weeks. The easy answer would be to throw both of those pitchers less, which he is doing with the fastball.

The problem lies in that the sinker could still be a nice weapon for him, even if it was just to change-up the eye level for the batter. The bigger issue appears to be its location. At this point it almost would help him more to work on keeping the sinker (and fastball) a bit lower in the zone than how much he is actually using it. This would also probably increase the amount of groundballs hit off of the sinker and decrease the balls hit in the air.

While it’s obvious where the issue lies, to me it also speaks of an easy fix for Junis. His problems appear to be more in where he is placing the ball with his hard stuff. While changing up the batters eye level is important, it does no good if you are leaving the ball in their wheelhouse.

It will be interesting to see if we notice an adjustment soon and if location is the biggest part of it. Junis has a great slider and if he can get his other pitches working he will be tough to hit. A tweak and a slight drop might be all it takes to get Jake Junis back on track this season.