Hitters Are Beating Corbin Burnes With Patience

No truly functional version of Corbin Burnes--with his raw stuff, the depth of his repertoire, and his control--should run a below-average strikeout rate. In 2021, he punched out over 35 percent of the batters he saw. That figure fell in 2022, but was still over 30 percent, which is elite territory for a starting pitcher. This year, though, he's only fanned 22.3 percent of opposing batters. That's downright pedestrian, especially in juxtaposition with his rising walk rate.

The problem has been hard to pin down, even for those of us who look closely at things like pitch movement, usage, and mechanics, using statistics and video. However, there is one way of slicing and dicing what he's done this year that lays his true predicament bare, at least with regard to his approach and execution from pitch to pitch. 

At Baseball Savant, the site where the bulk of publicly-available Statcast data lives, one can search for pitch location using an incredibly detailed set of zones, which are broken down into four categories:

• Heart: Pitches right in the middle of the strike zone, which are almost certain to be strikes but run the greatest risk of being hit hard
• Shadow: Pitches that, if the batter doesn't swing, might or might not be called strikes; these are the edges of the zone, where the finest craftsmen pound the ball most often
• Chase: As the name implies, this type of pitch relies on the batter expanding their zone to be effective. The pitcher is trying to induce a swing, while giving the hitter as little chance as possible to make productive (or any) contact on that swing.
• Waste: Pitches so far from the zone that they should hardly ever earn a swing. These are misfires, or else, they're designed solely to make a hitter think about a different pitch and set up the next offering.

This is a very helpful way of thinking about pitch location, although (as is inevitable when doing this kind of analysis) it does give pitchers a little bit too much credit. Like most things in life, pitch location contains a greater degree of error and randomness than we care to admit. Pitchers miss by so much, so often, that it's often untrue that a pitch that ended up in the Heart of the zone was actually intended as a challenge.

Nonetheless, with a sufficient sample, both the frequency with which a pitcher finds a certain attack zone and the value they get therefrom can be compelling data points. For Burnes, that's certainly true, and it all boils down to what happens when he tries to get hitters to flail away at stuff out in the Chase zones.

Here's how often hitters swung at each of his pitches when he threw them in the Chase zones, first in his extremely successful 2021-22 stretch, and then this year.

Other than his changeup, hitters are seeing and laying off everything in those zones considerably more often. All year, there's been some talk about his cutter getting too big and hitters spotting it earlier, but this makes clear the extent of that issue. It's a problem that perpetuates and exacerbates itself, too, because every pitch in this area that a batter resists is a ball, leading to a more hitter-friendly count wherein they can afford to be more patient on the next pitch in a similar spot.

Burnes is also spending more time in these zones this year, but the increase (about 3 percent of his total pitches) is not so large that I'm inclined to think his control has seriously declined. Instead, this feels very much like a case of hitters making an adjustment in their approach to a veteran starter, and of him and his new regular catcher struggling to make a quick counter-adjustment.

That might be changing now. Burnes's last outing, against the Giants, saw him allow just one run in seven strong innings, and his eight strikeouts and 16 swinging strikes both tied his season-high marks from a start in Arizona in mid-April. On the other hand, though, it took him 21 more pitches to reach those marks this time, and nearly all of San Francisco's batted balls were in the air. 

As I've written before, there are some very subtle mechanical things going on with Burnes this year, but they don't seem to be the drivers of his difficulty. They might be affecting his location more than it seems, but my best guess at the moment is that he (along with William Contreras, Victor Caratini, and the coaching staff) is still trying to discover a new optimization point--a new balance between attacking hitters and staying away from the barrels of their bats. He might need to trust his stuff more early in counts, in order to earn the jumpiness and poor swing decisions that characterize hitters once there are two strikes on them.

If this was just about one pitch, we could ask ourselves whether he's tipping it, or what might be wrong with his grip. Since all of his arsenal is affected, though, the smart money says that hitters are just outguessing Burnes right now. He's earning a stalemate in his game of chess with opponents. He needs to find a way to start pursuing checkmate again.