Overreliance: Michael Kopech Must Readjust Pitch Mix for White Sox to Extract Max Value

As the disastrous 2024 Chicago White Sox season slugs along, we as fans are reduced to thinking about prospect returns for veteran trade pieces and hoping that there's an emergence of young talent that could be part of a future turnaround. With each passing day, we're getting closer to all remnants of Rebuild 2.0 departing the South Side. While that's a welcomed proposition for many given the failures of this era, it's a sad reminder of the faulty bill of goods we were sold.

Seven years ago, we were told that Michael Kopech was a potential top-of-the-rotation starter who would be paired with the likes of Lucas Giolito, Reynaldo Lopez, and Dylan Cease to form a pitching staff that would be the envy of baseball. We know this didn't pan out, and frankly, it was never close to doing so . Kopech's tumultuous tenure with the Sox will most likely come to an end at the trade deadline, but while he's still here, it's important for him to string together quality outings to help the team extract as much value as possible . However, there are problems that have emerged as May is coming to a close.

For the season, Kopech has a 4.18 ERA , 12.55 K/9, 5.32 BB/9, and 1.90 HR/9 across 23.2 innings. For a high-leverage reliever, two of these numbers greatly concern me. The BB/9 and HR/9 figures are problematic for an arm tasked with getting outs late in games. Two things high-leverage relievers can ill afford to do is surrender free passes and long balls, and those have been issues for the big Texan.

I fear that part of the issue has been Kopech's overreliance on fastballs. There have been some interesting changes to his pitch usage in May, and the results can't be what the team has been looking for out of Kopech. The reason for the change hasn't been discussed yet, but there are some troubling things to take from it, albeit in an admittedly small sample size.

Overheated

Through April, Michael Kopech had a 4.41 ERA, 13.22 K/9, 4.96 BB/9, 1.65 HR/9, and a strong .293 xwOBA. During that time, he featured his four-seam fastball 77.9% of the time, compared to throwing his slider at 13.9% and cutter at 8.2% after adding the pitch to his arsenal this season. The slider and cutter proved to be effective pitches as both offerings were yielding soft contact with xwOBA below .200. The four-seamer was getting touched up a little bit, yielding a .335 xwOBA and all three homers.

When the calendar flipped to May, something with Kopech's approach flipped with it. So far this month, his slider usage has dipped to 5.1% as the biggest uptick in his arsenal is with the cutter at 15.3%. That means this month, he's throwing a fastball variant 94.1% of the time. In fact, Kopech has only thrown eight sliders the entire month. The offering yielded a .195 xwOBA through April, and now it has almost vanished.

When he's throwing the pitch, it's getting hammered. The slider has a 1.154 xwOBA in May, and you don't need to be a math major to realize that's not good. It looks in some ways as though the emergence of Kopech's cut fastball has taken away the effectiveness of the slider.  Throwing a fastball variant over 94% of the time isn't going to do enough to keep Major League hitters off balance, in my opinion. Removing a slider that has been an effective pitch just eliminates one other thing hitters must be mindful of when they step into the box in pivotal moments.

The decision to shift from the slider to the cutter as his primary secondary offering is puzzling to me. The slider was playing up since Kopech's shift to the bullpen with the velocity seeing a full 2 MPH uptick and leading to soft contact highlighted above. The shift toward using the cutter as the primary secondary offering may also be causing Kopech to lose the feel for the slider, and as a result, the few times he's throwing it, it hasn't had the effectiveness we've grown accustomed to with the pitch.

Unfortunately, this enhanced fastball-centric approach has hitters seeing the slider better than ever. Of the eight offerings during May, there hasn't been a single swing-and-miss on the pitch after it yielded a swing-and-miss rate of 42.9% during April. Hitters haven't chased a single slider out of the zone this month either, while they did a third of the time to open the season.

It may be a mere coincidence that incorporating the cutter at a higher rate this month has had a negative impact on the slider, but it's something that can't be ignored right now. Kopech's inability to offer a wrinkle to hitters when they step in the box will only allow them to sit dead red more often.

Diminishing Return

As alluded to above, Michael Kopech's days in a White Sox uniform are numbered. The Sox will surely look to deal the fireballing Texan ahead of the trade deadline to continue their efforts of restocking a farm system that doesn't have sufficient depth at the early phases of this rebuild. If Kopech's performance doesn't improve in short order, I think some within the fan base will be underwhelmed by the return the team receives.

There's a belief that the White Sox will come out of a future deal involving the righty with a quality prospect, but if he continues to walk hitters and surrender long balls at elevated rates, Chris Getz will lose any remaining leverage he might have. I'm sure more savvy organizations will see Kopech as a pitcher who can improve his results with a few modest tweaks, but his performance leading up to a future deal matters. And if his performance continues to be substandard, so will the return much to the dismay of some Sox fans.

At the present moment, I think there's an overvaluing of Kopech by some White Sox fans because they see the explosiveness of the arm and how it's played up in short bursts out of the bullpen. But again, the results matter. Teams aren't going to pay a premium in terms of prospect capital for a pitcher approaching 2 HR/9 and 5.5 BB/9. Kopech's decision to abandon the slider is having a negative impact on his performance and, in turn, on the future prospect return the Sox can receive should a deal happen in the near term.

In the coming weeks, I'm curious to see if Brian Bannister and Ethan Katz steer Kopech back to utilizing the slider more frequently as he's done through most of his career. The White Sox need Michael Kopech to string together a run of quality outings so they can extract maximum value for him at the trade deadline. The heavy fastball approach isn't working right now, and it needs to change quickly.

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