Jackson Merrill's Issues With Fastballs Finally Have An Origin

[Randy Holt]

Jackson Merrill's 2026 season has been a never-ending offensive spiral. Our @Gottie Chavez first looked at the San Diego Padres' center fielder back in April when it was becoming clear that he was struggling with timing against four-seam fastballs, feeding into a slow start. Then ,we were back in the Merrill business in May, when @N.B. Lindberg dove into Merrill's struggles that originated in the heart of the zone. He was expanding the zone early with little to compensate when he was working on pitches in the friendlier portions of it. 

In the month since the latter examination, things haven't gotten much better for Merrill in any respect. Sure, there was a decent blip of a bump in the power numbers — specifically against breaking pitches — but he has otherwise continued to spiral out of control at the plate. His numbers remain pinned down, with a .217/.273/.357 line and a 75 wRC+ to his name through more than three months in the books. 

The latest turn in Merrill's struggles comes courtesy of Timothy Jackson of Baseball Prospectus, who further established that Merrill isn't locked into an issue with his approach, but rather in his mechanics. As it turns out, there's a relationship between all of these pieces.

If one were to watch Jackson Merrill log a plate appearance or two over the course of a game, the eye test might indicate it was, in fact, his approach at the center of his 2026 issues. It's an easy conclusion to draw, especially when the player has seen his strikeout rate increase for a third consecutive season. Merrill's K% sits at 25.8 this year, more than three points above his 2025 rate and over eight percentage points higher than it was in his breakout rookie campaign of 2024. Declaring it to be an approach issue based on that, however, neglects the other side of the story. 

A rising strikeout rate points us in an approach-related direction, especially when we saw Merrill's swing and chase rates each rise slightly between 2024 and 2025. That's not what's happening here, though. Instead, the outfielder is actually swinging less than even his rookie year, at a 54.8 Swing%. His 35.4 percent swing rate on pitches outside of the strike zone is less than a point above his rookie year and a three-point cut from last year's rate. And while his batting line looks egregiously worse than an injury-riddled 2025 season, the contact rates look quite similar across the board.

Instead, where Merrill's issues live is in the blend of both making contact and making it of a certain quality based on his timing. Or, you know, a fusion of each of the pieces mentioned above. While that could be an approach issue, Merrill's problem is becoming more visibly of the mechanical variety. 

In those instances where he does make contact, Merrill is still doing so with authority. His 45.7 percent hard-hit rate is in the 74th percentile and comfortably above the league average of 39.1 percent. His bat speed being up from the last two years (73.5 MPH) likely helps, but that development on its own is not enough to drive production, especially because some other factors are helping to negate that. 

For one, Merrill's swing has gotten steeper. His 39-degree tilt is a couple degrees higher than each of the last two years, while his average attack angle was 10 degrees last year and is at nine in 2026 after being at six in 2024. At the same time, his swing has also gotten slightly longer, leading him to make contact farther out in front of the plate and, more importantly, farther away from his body. A long, upper-cut swing isn't going to be a BABIP darling.

Which feeds into how Statcast's new data, which Jackson mentions in his work, illustrates the problem as a mechanical flaw rather than something rooted in the approach. Let's focus just on the fastballs here, though:

The above is Merrill against fastballs in 2024, illustrated in red, and here in 2026 represented by that teal color. Our middle image there shows that he's closer to on time than he was even in 2024. No doubt that the swing speed has helped him there. However, the left graph indicates he's catching things closer to the end of the bat with greater regularity while ending up under fastballs more frequently. The result is a flyball rate to the opposite field at a 47.2 percent clip. Merrill was at roughly 32 percent in 2024. 

There's been a push to invest in fly balls to the pull side by myriad hitters across the baseball landscape the last couple of years. The rationale is obvious, in that pull side power is your greatest opportunity to create the highest quality of contact and, subsequently, create impact. Merrill is closer to on-time than he was in 2024, but he's squaring the ball up and creating fewer blasts while hitting just .071 on such contact. 

Therein lies our problem. Merrill has fallen just enough out of whack mechanically that he's unable to compensate no matter how hard he swings. As our writers here at Padres Mission posited earlier this year, it's very much a fastball issue. We just have more clarity on it now. Sure, there are some other factors weighing him down, embedded into the approach and against other pitch types. But as a major-league hitter, there's a better-than-not chance that your greatest success is going to come on fastballs. Merrill can't do that right now.

As Jackson indicated in his piece, though, that doesn't mean that Merrill stopped being a good hitter. Nor does it mean the changes being made are intentional. Regardless of their origin, though, they're holding him back and he's going to have to find a new way to compensate to get back. It's not the approach and it's not solely bad luck.

Once mechanics and, as a result, the fastball issue are sorted, we can worry about the rest.

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