This 2024 Trade Deadline pickup is breaking out

One of the most impressive swings of the 2025 season belongs to Kyle Stowers.

On May 3, the Marlins outfielder turned around a 101.7 mph fastball from Mason Miller, smashing it the other way for a walk-off grand slam. It’s the fastest pitch that any Marlins player has hit for a home run in the Pitch Tracking Era (since 2008). No one has hit a home run off a faster pitch this season, and it’s not particularly close.

The grand slam punctuated a four-homer week, which led Stowers to win National League Player of the Week honors.

Last July, the Marlins acquired Stowers and Connor Norby from the Orioles in return for Trevor Rogers. Stowers seemed like the third piece in a three-player deal, and he struggled, slashing .186/.262/.295 in 50 games after the trade. Entering this season, the 27-year-old had a career .600 OPS in parts of three MLB seasons.

That makes this year’s success all the more surprising. Among qualified hitters, Stowers ranks top-25 in batting average (.303), slugging percentage (.504), and weighted on-base average (.381). His barrel rate -- 19.5% -- is the sixth-best in baseball. And that grand slam off of Miller is a pretty good sign that things are finally falling into place.

“I’m a guy that, when I’ve been at my best, I use the whole field,” Stowers told MLB.com Marlins beat reporter Christina De Nicola. “I don’t necessarily try to. But when I can hit that fastball in the left-center gap, to me, mechanically, I’m in the best spot.”

He’s been doing a whole lot of that so far this season. Only three qualified hitters have a higher slugging percentage on non-pulled balls than Stowers:

1. Aaron Judge (NYY): 1.123 SLG
2. Kyren Paris (LAA): 1.077 SLG
3. Logan O'Hoppe (LAA): .947 SLG
4. Kyle Stowers (MIA): .898 SLG

That puts Stowers above the likes of James Wood (.889) and Shohei Ohtani (.889), two sluggers known for their ability to drive the ball the other way. Take a look at the spray charts of Stowers’ hits in each of the last two seasons. He’s succeeding by hitting the ball to left-center -- which wasn’t the case in 2024.

“I kind of noticed toward the end of (last) year that I was starting to fly out to the track a lot more,” Stowers said. “There was like, about five or six balls that I can look back on last year that were balls to the track that I thought I hit a lot better than I did. I would go back and see the exit velocity and be like, ‘that doesn’t feel right.’”

Stowers said he spent the offseason filling out his 6-foot-2, 215-pound frame, which has in turn made him stronger. That’s certainly helping. But there’s more under the hood, too. With Statcast’s latest batting stance metrics, we can track some of the other subtle changes fueling Stowers’s early-season success. The graphic on the left displays his position in the box in 2024, while his 2025 stance is on the right.

The first thing to notice is that Stowers is standing nearly three inches deeper in the box, which gives him a bit more time to read the pitch. It’s a decision driven mostly out of comfort -- “that’s all I really think about,” Stowers said. And while it’s not a drastic change, it’s not insignificant, either. For one, it helps explain why Stowers has slashed his chase rate against breaking balls by 11%; he’s down to a 30.2% chase rate against breaking pitches, which is right at league average.

Standing further back in the box also allowed Stowers to change where he makes contact with the ball -- letting the ball travel deeper.

A hitter’s intercept point -- where they make contact with the ball — can tell us a lot about their skillset. Players who hit the ball out in front, like Jose Altuve, tend to sell out for pull-side power. Those who let the ball travel deep are deft at hitting the ball to all fields, like Freddie Freeman.

This season, Stowers is making contact an average of 0.9 inches in front of the plate -- which is an inch closer to home plate than the average left-handed hitter. By comparison: When Stowers made his season debut last May, his intercept point for the month was 4.4 inches in front of home plate.

Together, those metrics help show why Stowers is suddenly hitting the ball with authority to all fields. Take a look where he makes contact with the ball on a three-run shot against the Reds, relative to the plate:

It’s not a strategy that works for everyone -- especially given the advantages of selling out for pull-side power. But it’s successful for Stowers in part because of elite bat speed: He can let the ball travel deeper without sacrificing the ability to get the barrel around to the ball, still making contact with plenty of force.

Stowers’s average bat speed is 74.5 mph, which is in the 87th percentile -- 0.1 mph ahead of Ben Rice, whose own resurgence is tied to one of the largest year-to-year bat speed gains. We can see his year-to-year improvement in the bell curves below, with the orange curve -- 2025 -- showing that Stowers improved his floor, as well as his ceiling.

From 2024 to 2025, Stowers added nearly a full mile per hour of bat speed, which is even more impressive considering his baseline. If we look at the pool of qualified hitters who had a bat speed above league average (71.5 mph) last season, only eight have seen a larger year-to-year increase than Stowers. That group includes NL MVP candidates Corbin Carroll and Pete Alonso.

Not only is Stowers swinging faster; he’s doing more damage, too. In particular, he’s smashing fastballs -- nearly doubling his slugging percentage against them.

Stowers against fastballs

2024: .280 SLG // .238 wOBA // one home run
2025: .538 SLG // .410 wOBA // five home runs

For this, Stowers credits the step-up drill, which looks a lot like it sounds: In the cage, he stands much closer to the machine than he typically would, while programming it to pepper him with 100 mph fastballs. He’ll take 40 swings a day from this abbreviated distance, 'stepping up' to the pitch.

“Then, when you go back to the normal distance, it helps you process the ball a longer time and see the ball a little better,” Stowers said.

Ironically, that’s what his new position in the batter’s box is doing, too.

It’s why he can drive fastballs the other way with ease -- like this 108.9 mph shot off Dodgers right-hander Yoendrys Gómez, courtesy of a 75.5 mph bat speed. Thanks to a series of subtle changes, this may become the norm for Stowers moving forward.