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Breaking down Miles Mikolas’ poor start to the season

Are there brighter days ahead for the Cardinals starter?

St. Louis Cardinals v Seattle Mariners Photo by Alika Jenner/Getty Images

St. Louis Cardinals starting pitcher Miles Mikolas was handed a 2 year, 40-million-dollar extension this off-season. The hope was he’d be able to provide some front-end stability to a rotation that was looking a bit shaky. At the time of signing, it looked more than sensible seeing as Mikolas was coming off a season where he threw 202 ⅓ innings, a rarity in today’s game, and posted a 3.89 xERA. Unfortunately, though, Mikolas has so far put together career-worsts in nearly every pitching statistic to start this season. Through his first five starts this season he’s to a paltry 7.31 xERA with a 1.89 WHIP. Down below we are going to dive deep into the start of his season to try and identify what’s gone wrong for him.

His pitch quality

This is the weird part for me personally. When a pitcher is struggling over a stretch of multiple starts or appearances, the first two things I check are their spin rates and pitch movement. Traditionally, when a pitcher’s performances slip at least one of these two are the first things to go which can give us an easy indication as to why they are struggling.

Miles Mikolas spin rates

Spin rates 2022 2023
Spin rates 2022 2023
Slider 2,382 2,365
Four seam 2,292 2,303
Sinker 2,232 2,225
Curveball 2,547 2,498

Mikolas pitch movement

Pitch movement Vertical 2022 Vertical 2023 Horizontal 2022 Horizontal 2023
Pitch movement Vertical 2022 Vertical 2023 Horizontal 2022 Horizontal 2023
Slider 31.1 inches 34.0 inches 3.9 inches 3.8 inches
Four seam 16.3 inches 16.2 inches 4.9 inches 4.9 inches
Sinker 19.5 inches 20.2 inches 13.3 inches 13.6 inches
Curveball 63.3 inches 62.6 inches 8.7 inches 8.8 inches

So, the weird thing with these numbers is they are effectively the same or better with just about all of his pitches. The change in his spin rates is largely nothing — as up to as many as 75 RPM is not a major difference and none of his pitches had nearly that much of a change. In terms of his pitch movement the only difference of note is his slider gaining nearly 3 additional inches of vertical movement. We can just about rule out the overall quality of his pitches being the reason he has gotten off to a sluggish start this season.

What's the quality of contact like against him?

After checking a pitcher's spin rates and movement, which we did above, the next thing I like to look at is if the batted ball profiles against the pitcher changed. The short answer for Mikolas is a resounding yes. Batters are destroying his pitches consistently thus far.

Mikolas average exit velocity against this season has jumped all the way up to 91.3 MPH (19th percentile). To me that number explains a lot of his outcomes and batted ball misfortunes — like a career-high batting average on balls in play of .402 and 19.4 percent home run per fly ball rate. The harder the contact, the higher the expected metrics and the overall likelihood of the contact causing damage. This is a number that might regress to the mean a bit as in 2021 his average EV was 87.8 MPH and in 2020 it was 87.7 MPH. Allowing a number that high is not the norm for Mikolas, but it is a concern to keep in mind.

The next disheartening trend for me is his dip in producing ground balls and sharp increase in allowing line drives. Last season his ground ball percentage against was 45.9 percent, a number that traditionally is right around league average. This season it’s only 33.7 percent. On the other hand, his line drive percentage was 23.8 percent which, like his ground ball mark last year, sat at about average. That’s not the case in 2023 as it’s jumped all the way up to 38 percent. We’ve also seen a small dip in his pop-up percentage as it’s gone from 5.1 percent to 3.3. While that might not seem like a lot on the surface, pop ups are the next best thing to strikeouts as they are effectively guaranteed outs. Part of the reason this is significant to me as well is it gives us a slight hint as to how his fastball is playing. Traditionally, pop ups come off of fastballs that are high in the zone and hold their plane a bit longer, causing hitters to work under it and pop it up. A decrease in that area could tell us his four-seam simply isn’t riding in the top of the zone as well this season. So to recap, less ground balls, more line drives and a much higher average exit velocity against Mikolas thus far. Also known as a very bad recipe for success for pitchers.

Is there any change in his control?

For the most part no, his in-zone percentage this year is 52.7 percent, identical to last season’s mark. His edge percent is 45.4 percent, the same exact number that he posted in 2022. His meatball percentage of 7.6 percent is, pretend not to be surprised here, the same as last year. When breaking down his pitches individually as well there isn’t a pitch that he is suddenly struggling to throw in the zone as every number is about the same as last year.

So, is Mikolas going to return to his 2022 form?

Short answer, yes, I believe so. His stuff has not diminished according to the metrics which is king. He’s still throwing strikes, producing chases at a similar rate and is working the edges well. The biggest concern is his struggles in quality of contact. The changes are significant in that area and concerning, however, with only 25 innings into the season thus far, I do think as the season continues that is going to regress to his career average. In his last start against the Seattle Mariners, his average exit velocity was 89.4 MPH, an indicator to me that Mikolas is slowly getting back into form.