Brad Peacock Might Finally Have An Answer For Lefthanded Hitters

Brad Peacock has been a lot of things in his career. A near-afterthought as a draft pick, a top-50 prospect, a starter with an unsightly walk rate, injured with bone spurs near his spine, a nifty reliever, a great swingman…they’re all apt descriptions of the various phases he’s experienced. This year, he’s back in the rotation for the Astros as they’re primed for another season of success. Whether in an upswing or a downturn, though, lefty hitters have always been a bugaboo for him.

He came into 2019 sporting a wOBA against lefthanded hitters that was 29% worse than the average righthanded pitcher since he came into the league. I wanted to round that to 30% for the sake of convenience, but then I checked how Peacock has performed against same-handed hitters compared to other righties in the same time frame. Get this — he’s been 29% better at limiting quality contact than his peers. Talk about wild!

But back to how he fares against lefties. He has a three-quarter arm slot and his best pitches — his fastball and slider — aren’t necessarily ideal to go to battle with against them. With that in mind it’s understandable that he could have his limitations; that his ultimate effectiveness might be limited by the same things that got him to the Majors. Just consider what he’s thrown when facing a lefthanded hitter through his career:

peacock v lefties career
There are a couple clerical-type things to note here. One is that we could merge Peacock’s two-seamer (FT) and sinker (SI) into 229 total pitches. Even if we want to split hairs and distinguish them from each other, odds are infinitesimal that Peacock was trying to throw two different pitches. It’s just a pitch classification quirk. The other is that anything thrown by a pitcher less than about 10% is something we don’t need to sweat. It probably isn’t offered enough to really buy into the data it produces. So we can eliminate the two-seamer as a whole to get a closer look at how Peacock really approached lefties from the time he debuted in MLB through last year.

That leaves us with a four-seamer, a knuckle curveball, a slider, and possibly a changeup. Based on usage, let’s draw our focus tighter to just the breaking balls. Here’s where he located them:

peacock HHEEAATT

That’s from the catcher’s perspective. He alternated location with each, sometimes trying to get chases low and in and sometimes trying to backdoor them over the plate. They’re distinct pitches and that’s usually good. But in this case, maybe not so much. Peacock’s curveball has always dropped between six and 11 inches more than his slider. Meanwhile, its side-to-side movement shrunk from a four inch difference with the slider to less than an inch in the last two-plus seasons. Locating the pitches in different spots could have given lefty hitters the chance to distinguish the break on each pitch, line it up and drive it, or spit on it and wait for a fastball. With all that deep yellow outside of the zone above, there was probably a good chance for a walk, too.

In his first start of 2019, he changed things against lefties. To the pitch mix!

peacock peeitch meeix
Ok, so let’s ditch the two-seamer/sinker amalgamation. Let’s also ditch the single cutter (FC), because it was probably just a bad slider. We can take or leave the five changeups, and since we already left them earlier, we’re going to do it again. We’re going to continue focusing on only the four-seamer, the knuckle curveball, and the slider.

The first thing that jumps out is the fastball is down below 50% usage. The next thing that sticks out is the breaking ball preference has flipped. By flipping the script, Peacock got four called strikes on sliders to lefties in his 2019 debut, plus one whiff. The lefties let the curveball go and it became a ball half the time. 

There’s one more thing about how Peacock employed his breaking balls against lefties to start the season. Here they are in heatmap form from the catcher’s perspective again:

peacock heat

Both pitches fell to the same lower, inside corner. With the side-to-side break less than an inch apart from each other, and the curveball dropping more than an additional 10 inches, Peacock used them in tandem to cause fits for lefties.

Think of this with the heatmap as an aid. The pitches most frequently fell to the black dot below the zone, but the pitches that created the gradation of maroon out to orange up and into the zone are the ones that made it so hard for the hitter to decide whether to swing.

You might be thinking, “Big whoop. The Astros played the Rangers in Peacock’s first start. They stink.” You wouldn’t be wrong. They’re projected to win about 75 games, give or take a few. But Texas offers some dangerous lefties. Nomar Mazara, Joey Gallo, Rougned Odor, Shin-Soo Choo, Asdrubal Cabrera, and Ronald Guzman combined to go 2-for-14 against Peacock. The lineup was stacked with established lefty big leaguers (save for Guzman) whose wOBA was between average and 50% above average against righties as recently as last year, and they were collectively helpless. 

The season’s about a week old. What’s happened so far is by no means an indicator of what will continue to happen. But Brad Peacock might have changed his approach to lefties and that could be a big deal. It might not solve his times-through-the-order problem, where he’s 75% worse than his peers the third time seeing an offense. He’s also 25% better than them when seeing hitters the first and second time, though, so an uptick in efficiency could produce some scary-good results. The Astros have pitchers in the system like Forrest Whitley and Josh James, plus others, who could eventually take Peacock’s rotation spot. For now, he’s locked in, and might have a new trick up his sleeve to help keep it that way. 

All data from Statcast unless otherwise noted. Feature photo Ron Schwane/Associated Press.



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