Reports of the Corbin Burnes renaissance are exaggerated

Much has been made of Corbin Burnes’ strong start to the season’s second half.

The right-hander’s recent results more closely resemble what the Brewers have come to expect from the former Cy Young Award winner. After pitching to a pedestrian 3.94 ERA with a 23.1% strikeout rate in eighteen starts in the first half, Burnes has posted a 2.63 ERA and 29.3% strikeout rate in six starts since the All-Star break.

The leading narrative is that the improvements are due to adjustments Burnes made during the break. Burnes indeed made a handful of tweaks. He’s using his curveball more against left-handed batters. He also modified his slider grip to give it more sweeping movement, which better separates it from his cutter and curveball.

Furthermore, Burnes has been more liberal with how he uses his cutter in the strike zone. Until the All-Star break, he focused on just two locations for the cutter, throwing it almost exclusively on the outside part of the plate to right-handed hitters while mixing in some back-door cutters to left-handers.

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Burnes recently acknowledged a flaw in his approach with the cutter that was evident since April: right-handed hitters could sit on cutters low and away because he wasn’t showing them any other locations. He has now taken steps to be more unpredictable with the pitch, throwing it to both sides of the plate against righties in the second half.

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However, these changes might not be enough to carry Burnes to a dominant stretch run, rendering the reports of his return to dominance premature. Pitch sequencing remains one of his most significant flaws, and the supposedly new-and-improved Burnes pitches remarkably similarly to his first-half counterpart.

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Burnes has made just one discernible change to his pitch mix, using more curveballs against left-handed hitters when ahead in the count. This adjustment has come at the expense of his changeup.

Making the curveball his primary secondary in such matchups instead of the changeup makes sense. Burnes’ cutter averages 94.4 mph, and his changeup averages 89.4 mph. His 79.7 mph curveball creates greater velocity separation.

The change has made a difference. Burnes held left-handers to a .261 wOBA in the first half, but they’ve managed just a .159 wOBA against him in the second half.

On the flip side, little has changed against right-handed batters from a pitch selection standpoint.

Despite developing a new slider that profiles as a weapon against righties, Burnes is not utilizing it. He’s throwing fewer sliders to righties than in the first half, including in two-strike counts when throwing a put-away breaking ball makes the most sense. If anything, he is turning more to his sinker, which has below-average movement and profiles as the worst pitch in his arsenal.

Meanwhile, Burnes has not shied away from his cutter against righties, using it just as often as he did in the first half in nearly every count. Despite seeing it in more areas of the zone, righties are still sitting on it and doing damage. After posting a .307 wOBA against the cutter in the first half, they’ve produced a .321 wOBA against it in the second half. The cutter is yielding fewer chases and whiffs from righties than it did before the All-Star break.

While the improvement against lefties was welcome, Burnes needed improvement most against righties. They posted a .300 wOBA against him in the first half, his worst mark since 2019. Burnes has not meaningfully changed his pitch mix against right-handers, so the results have not changed, either: a .302 wOBA in the second half.

Much of Burnes’ strong performance in the second half thus far is due to his complete dominance over lefties. He’s had more opportunities to face them since the All-Star break, with 55.3% of his batters faced being left-handed compared to 51% in the first half.

Opposing managers who roll out a lefty-heavy lineup against Burnes are playing right into his plan of attack, but teams could soon catch on and load up on right-handers who can jump on the cutter. If that happens and Burnes refuses to mix in more sliders and curveballs, he could be in for a reoccurrence of the struggles that plagued him in the first half.