I will always have an affinity for hitters with a knack for vertical bat variability. To effectively cover pitches at different heights in the strike zone, a hitter has to vary the angle of their bat relative to the ground to create lift. To hit a pitch at the top of the zone for a line drive, the bat should be flatter, and to lift a pitch at the bottom of the zone for a line drive, the bat should be steeper. It’s a simple concept that some hitters can execute with more consistency than others. Jackson Merrill is one of those guys.
When I first really started getting into the mechanics of hitting, Mike Trout was the dude who made it easy to understand vertical bat variability. Vintage Trout’s lower half looked almost identical across all swings, but depending on the height of the pitch, his entire torso angle would adjust. Through the years, players like Michael Brantley, Freddie Freeman, and Trea Turner have all executed impressive levels of vertical bat variability, too. And unsurprisingly, they all maintained (or still do) strikeout rates well below the league average with great gap-to-gap line drive skills. When Eric Longenhagen first compared Merrill’s swing to that of Brantley, I became very impatient anticipating what the Padres outfielder would do in the big leagues. So far, he’s exceeded expectations.
Through his first 121 career games, Merrill has hit for a 125 wRC+ with a .290/.321/.484 slash line. Over the past month, he’s found his power stroke to go along with his superb line drive swing, and during that span, he’s been one of the best hitters in baseball, with a 182 wRC+ across 104 plate appearances. It’s come at a good time for the Padres, who have picked it up and are only three games behind the NL West-leading Dodgers.
Merrill’s sound mechanics and production at the plate are all the more impressive considering that he is still just a 21-year-old rookie who is also learning a new position. Although his outfield experience in the minors was limited to 45 innings in left field last year at Double-A, he’s already turned into one of the top defensive center fielders in the game (6 OAA).
His ability to go down and get it with the best of them while still covering the top of the strike zone is the key to his success so early in his career. Below is a table highlighting his performances in both the upper and lower thirds of the zone:
Merrill Performance by Vertical Zone
| Zone | xwOBA | League Rank* |
|---|---|---|
| Upper Third | .381 | 27 |
| Middle Third | .432 | 29 |
| Lower Third | .386 | 25 |
SOURCE: Baseball Savant
*Out of 194 batters to see at least 1,250 pitches as of Aug. 20
Elite hitters have all different shapes of production. Juan Soto mashes everything at the top of the zone, Aaron Judge crushes everything in the heart, and Yordan Alvarez demolishes everything down low. But it’s uncommon for hitters to be this productive on both high and low pitches. In fact, among the 194 hitters who’ve seen 1,250 pitches this season, only two other players have xwOBAs that rank in the top 30 on pitches in both the upper and lower thirds of the zone, Ketel Marte and Marcell Ozuna, who are two of the best 11 hitters in the game by wRC+. Merrill and Ozuna are the only two hitters with top-30 xwOBAs in all three vertical thirds.
As I said before, a hitter needs to employ a flatter swing path at the top of the zone and a steeper one at the bottom. Sounds easy enough, but the tricky part is generating enough bat speed across a range of bat angles to make it work from a damage perspective while maintaining the body control to make contact. What’s notable here is how Merrill does this: Unlike most hitters, Merrill keeps his bat vertically oriented against low and high pitches, which allows him create enough lift to shoot the gaps no matter the height of the pitch. It’s a balance of strength and finesse that Merrill seems to have mastered.
I could throw a bunch of numbers at you to explain this particular skill, but the best way to understand this is by watching what he does with his body and bat. Let’s take a look:
Upper Third
Before watching the lower third swings, here are a few quick notes. He maintains his posture and shoulder plane during all three of these swings. Because of that, he keeps his bat on the same vertical plane as these pitches so he can square up the bottom part of the baseball to create backspin but not get so far under it that he pops them up. Also, his torso backbend on the second swing is fantastic. This move is most noticeable from a hitter like Shohei Ohtani, who right before contact bends his upper body backward to give his barrel space to get behind the ball. Few hitters have the necessary upper body or t-spine flexibility to do this; Merrill is one of them. Okay, now onto some swings in the lower third:
Lower Third
Pay attention to his back shoulder on each of these swings. Merrill’s body and bat are moving together as he swings, and he uses his back shoulder as a guide to get his barrel on plane with pitches in the lower third. Whether it’s a back-foot breaking ball or a dotted heater away, his back shoulder angle lines up his swing.
The important thing to take away from all of this is Merrill has a great understanding of how to use his upper body to get his bat on plane with pitches at different heights. That’s the elite skill carrying his game right now. He has the talent to develop additional tools and sharpen the ones he currently owns as he gains more experience. He’s already started tapping into his power more over the last month or so. He still chases too many pitches and struggles against lefties, albeit in a small sample of plate appearances (70 wRC+, 127 PA), but again, he is 21 and figuring things out in his first big league season. What we’re seeing from him right now is essentially his starting point as a hitter, and that’s really exciting.
