Handing the ball to Burnes in such a situation would typically be a source of comfort. That has not been the case this season. In 10 starts, Burnes owns a 3.97 ERA, 3.90 xERA, and 4.81 FIP.
It would be easy to downplay those numbers as nothing more than a slow start were they not a continuation of a trend that began last summer. Since the start of last August, Burnes has pitched to a 3.96 ERA (95 ERA-) and 4.05 FIP (97 ERA-) in 23 starts. The former Cy Young Award winner is approaching an entire season’s worth of work in which he has been a league-average starter rather than an elite hurler.
The downturn is not due to declining stuff. While Burnes has lost a tick of velocity on his cutter this year, he still averages 94 mph with the pitch and regularly visits the upper 90s. According to the Stuff+ metric at FanGraphs, Burnes’ stuff is not at its 2021 peak, but he still possesses the sixth-best rating among qualified starters.
Burnes, for his part, is largely satisfied with how he has thrown the ball, particularly his signature cutter.
Here’s Corbin Burnes’ thoughts on his outing tonight, the season so far and swings he’s seeing against the cutter: pic.twitter.com/42Vam1Is6j— Curt Hogg (@CyrtHogg) May 23, 2023
Burnes is a meticulous self-evaluator. He keeps a journal in which he grades how well he executes each pitch he throws. In this instance, his assessment is correct. While he has made some mistakes over the plate, there are no meaningful differences in his cutter execution compared to his 2021 and 2022 seasons.
Burnes is not missing down the middle any more than he has in past seasons. Instead, opponents are ambushing at an alarming rate when he does miss. Notice how sharply his xwOBA on middle-low pitches has risen within the past two years.
The problem lies in the criteria of Burnes’ evaluation. He presupposes that the same game plan he has followed for years will continue to yield success. In reality, this process is working against him.
Burnes has become predictable. It began last summer when he developed a platoon split due to left-handed hitters hunting his cutter and changeup pairing on the outer third of the plate. After an April 5 start against the New York Mets in which Burnes allowed a pair of home runs, Brewer Fanatic’s Tim Muma noted that hitters were sitting on pitches in the lower third of the strike zone.
Anticipating hard stuff at the bottom of the zone is a fruitful approach because it’s where Burnes does most of his work. Take a look at his location map over the past three seasons.
With the exception of his curveball, Burnes’ entire arsenal is built around lateral movement. He does not possess a riding four-seam fastball but instead makes the baseball cut or run. As such, he will always find the most success in the lower third of the zone. However, his approach is too extreme in that he rarely changes eye levels.
Opponents can eliminate the upper third of the zone because Burnes rarely uses it. As a result, his effectiveness on pitches at the knees has diminished over time.
Burnes remains tough to square up when he executes low to the glove side, which speaks to the quality of his stuff. However, honing in on the lower portion of the zone has enabled opponents to do severe damage on pitches that leak over the middle. It has also helped hitters make more contact on pitches that were once among Burnes’ best swing-and-miss weapons.
In 2021, Burnes induced plenty of swings and misses in the lower third of the strike zone. Opponents started to make more contact on such pitches last year and now put plenty of lower-third offerings in play.
Not only can they sit on a location within the zone, but hitters can also often sit on a specific type of pitch. Burnes has thrown his cutter at least 50% of the time in every season since 2021. This year, it has yielded a .369 xwOBA, by far the worst of his career. Meanwhile, Burnes’ secondary pitches have remained effective offerings.
While most pitchers must establish their fastball to be effective, one can argue that Burnes should not be leaning so heavily on a single pitch when he has five in his arsenal, including a pair of excellent breaking balls.
Now that hitters have developed a plan to beat Burnes—hunting hard pitches low—the onus lies on him to adjust. By reducing his cutter usage in favor of more breaking balls and flashing his cutter and sinker up in the zone, he can reinsert himself into the driver’s seat and keep hitters guessing.
The greatest hurdle to a turnaround is Burnes’ willingness to change. His remarks after his last start are not those of a pitcher who recognizes the flaws in his approach and plans to make adjustments. Burnes sounds like a pitcher convinced he is doing the right things and will find results by staying the course.
The right-hander also has a history of resistance to potential changes to his pitch mix. Burnes struggled through a nightmare 2019 season largely due to a four-seam fastball against which opponents slugged .823. Meanwhile, hitters slugged .306 against his slider. When approached about using his elite slider more often, Burnes pushed back against the suggestion.
“We keep getting beat by the heater,” said Corbin Burnes, who goes on to explain why the fix for that is not as simple as you might think. pic.twitter.com/s65xWJZ1fy— Adam McCalvy (@AdamMcCalvy) April 17, 2019
With four of their starting pitchers currently on the shelf, the Brewers cannot afford for Burnes to continue spinning his wheels. The Brewers need better from Burnes atop their rotation, and it starts with an openness to adjusting his plan of attack.