More Like Flat Wallner: Twins Slugger Matt Wallner's Swing Path is Much Different (and Worse) Lately

In the ninth inning of the Twins' latest demoralizing loss, the Milwaukee Brewers issued Byron Buxton an intentional walk. They put the winning run on base and gave up the platoon advantage, just to trade having to face Buxton for getting to face Matt Wallner. It was, in a sense, a risky maneuver. With Buxton's speed, a double by Wallner would have ended the game, and the chances of a double-steal by Harrison Bader and Buxton were not insignificant. Right-handed Brewers closer Trevor Megill is, like most righties, better against right-handed batters. Yet, the visitors felt comfortable going after Wallner instead of Buxton. It paid off.

On a 2-0 pitch, Megill threw a fastball on the inner third at 98.7 miles per hour. It's never easy to hit 99, but as such pitches go, this one was manageable. It's the kind of pitch you need your elite power guy to hit a long way, especially in that situation—and especially with the benefit of a count in which he could look for that pitch and try to gear up for it. Unfortunately, Wallner popped it up, harmlessly, for the second out of the inning.

This is a pattern, lately. Wallner is hitting an atrocious .164/.243/.418 since his return from the injured list on May 31. Though his strikeout rate this year is a career-best 29.1%, he's become more all-or-nothing than ever at the plate, because he's popping the ball up- or hitting it weakly more often than in the past.

The problem lies in his swing path. Here are the average swing tilt, bat speed, attack angle, attack direction and contact point numbers for Wallner, in each month in which he's had substantial playing time since the start of 2024. 

Wallner has lost a little bit of sheer bat speed, but he had that to give, and then some. What he couldn't afford to lose, however, was the tilt on his swing. The way his body and bat are working, now, he's getting out around the ball far too much, and catching it too far out in front of himself to get the ball flush on the barrel. Instead, though he's often able to make contact, he's frequently hitting it straight up in the air.

It might initially surprise you to hear that a flatter bat makes for more pop-ups, but if you think about it a bit, it's easy to see how it happens. Consider some side-by-side screenshots of Wallner at the contact point. Here's a comparison between a pitch on which he homered last August, and one on which he popped up to the middle of the infield in Seattle this year.

As you can see, the ball on the left was a few inches lower. That's key. Wallner's adjustment appears to be an effort to cover the top of the zone better, because his higher-tilt swing did lead to lots of whiffs on fastballs up around the letters. Equally obvious, though, is the tradeoff. A tilted swing path means that if you're slightly off on timing, you can still hit the ball on a productive trajectory: a high line drive, or a fly ball that will carry. It might go foul, or slice oddly to the opposite field, but it's likely to be a ball that goes forward more than up or down.

A flat swing puts you at greater risk of hitting the top or bottom of the ball, though it makes it more likely that you make contact with it at all. Here's another side-by-side. One shows a home run Wallner hit against the White Sox last summer; the other shows a ball on which he flew out to right this April.

Here, too, the ball he crushed was a bit lower, and your temptation might be to decide that he just needs to set his sights lower with this new swing—or even that the only reason why his swing looks flatter is because he's swinging at higher pitches. It's not that, though. From the center-field camera, it's hard to tell, but he's also too early on the ball on the right. That means both that he's getting to it a hair sooner, before it has time to drop those precious few millimeters; and that he's less able to manipulate the barrel of his bat to find the ball. 

The change in his average tilt (and the other metrics) still shows up if you isolate pitches in particular locations, but just to prove that location isn't the sole issue, here's a ball from this month on which he caught the top half, rather than the bottom.

That's a pretty fat fastball, below the belt and with plenty of plate around it. The Twins need Wallner to elevate that ball, especially with a runner on third and one out. Unfortunately, this version of his swing makes his barrel much less accurate than it used to be.

To see a bit of the biomechanics involved, here's a side-by-side set of screenshots from Baseball Savant's visualization tool for the new swing path metrics they provide. These are both from the frame of the animation where Wallner starts to get on plane with the incoming pitch—where the bat stops its downward travel from above his shoulder to the hitting zone and begins tracking uphill, to find the incoming pitch.

As you can see, that change is happening a bit earlier in the arc of his swing this year. Wallner's getting on plane while his left arm is still roughly level with his back leg, whereas in 2024, he was already steering forward and opening his front shoulder more by that point. Were his swing tilt the same, that could (plausibly) be a good thing, but there are two problems here:

1. Early Bat Speed: In the image on the left, from last year, you can see that the momentary speed of his barrel is already 73 miles per hour, an extraordinary number. For a hitter to generate that much speed that early in their swing, they have to have generated some tilt, to give their body and their implement room to get moving. On the right, he's only at 70 mph. Remember, though he's slightly down this year, he gets to nearly the same final swing speed at contact—but this means that more of that speed is coming in the final phase of the swing this year, so he can't control his barrel at all as it flies through the hitting zone. It also means that if he's slightly late, this year, he's unable to hit it as hard as he could if he was slightly late last year.
2. The Flattening: The stills don't reveal it, but we know it, and you can see it for yourself if you visit the Savant tool and watch the full animations. Wallner's swing isn't much steeper early, while the bat is behind him. That all comes as he brings it around, staying a bit more upright and reaching more. Remember how he's also catching the ball farther out front, in terms of contact point? That's because his swing sweeps long and flat through the area just in front of him, over the plate. He's less prone to whiffs, in theory, but his timing is so off that he's whiffing more than in the past, anyway. He's hitting some balls he would have missed last year, but he's also mishitting some balls he crushed last year. The late acceleration of his swing means trying to get around the ball more, and doing that means not staying through it as well.

Wallner could figure this all out fairly quickly and get right back to being an elite hitter. He has a fairly solid understanding of the strike zone; exceptional bat speed; less loop and hitch in his attack than many hitters with similarly vicious hacks; and sneaky secondary skills, like his speed. However, he seems to be making an intentional evolution aimed at becoming more complete at the plate. If that's his goal, so far, it's been a noble but doomed attempt. In all likelihood, the right thing for his profile is to get back to getting more tilt in his swing path. There will be other necessary adjustments once he achieves that, but without it, he might continue to miss hittable pitches at times when the Twins desperately need his power to play.