Did Rogers Centre kill Vladimir Guerrero Jr.’s power?

Whenever the post-mortem is compiled on this Toronto Blue Jays season — they’re still very much in the hunt for a wildcard spot — it won’t be hard to find culprits for how they didn’t quite manage to take the next step from a good team to a power that most in Ontario were expecting (f eels like a theme up there). Alek Manoah going from a Cy Young candidate to a modern dance interpretation of a malfunctioning fireworks barge would probably be top of the list. George Springer aging five years in one winter didn’t help much either. Daulton Varsho’s offense not coming anywhere near matching his defense might be another. But Vladimir Guerrero Jr.’s loss of power might be another.

Except Vladito’s power disappearing into the ether is one of the great mysteries of this season.

Looking over Guerrero’s contact numbers and type, one wouldn’t think too much is wrong. He’s hitting the ball slightly harder this year (93.4 MPH average exit velocity vs. 92.8 in 2022). His launch angle is actually double, 9.4 from 4.8 last year, which should have resulted in more homers than his line-drive-heavy 2022. The nine-degree launch angle is the same as his 2021 season where he hit 48 homers.

Vladito’s walk and strikeout percentages are almost identical, and certainly, there isn’t enough of a difference to explain a nearly 50-point drop in his slugging. He’s swinging at slightly more pitches in the zone than last year, but isn’t chasing any more pitches, which can kind of be gleaned by the fact that he’s not striking out any more than he has before.

The direction of his hits provides no clues either, as his pull percentage, center percentage, and opposite field percentage are nearly on the nose of last season and the season before that, all within a percentage point of each other. This is the same guy in approach and contact.

One explanation put forth is that when Vlad has been hitting the ball in the air — which he should be — he’s been hitting it up the middle more often. Which is true, as on fly balls he’s hit 41 percent to center vs. 36.6 last year and 37.6 percent in 2021. But that doesn’t seem like quite enough rise to explain this.

Getting into his home-road splits, things start to come into more relief. In road games, Guerrero Jr. is slugging .502, while just .355 at home. Last year, he slugged .511 at home. Strangely, on the road he’s been more pull-happy, pulling 42.5 percent of his contact, though on just fly balls his distribution of contact in the air has remained the same. At home, Vlad is only pulling 18 percent of his fly balls, down 10 percentage points from last year.

When Vladito has pulled the ball in the air in Toronto, he’s slugged 1.091, which is half of what he produced doing so in the previous two seasons (2.672 and 2.154). Meanwhile, his slugging on the road when yanking fly balls toward left has stayed consistent from 2022 to 2023 (1.778 to 1.412, a drop but nothing like at home).

This measure of ballpark factors for Rogers Centre might have something to do with all that. The Jays moved the walls in a few feet in left this year, though they were also raised a touch. Last year, the former SkyDome was ice cream for right-handers, with a 128 HR Park Factor for righties (28 percent higher rating for homers than average). This year that rating is 94.

Guerrero Jr. isn’t the only right-handed hitter affected. Matt Chapman has seen a 60-point drop in slugging at home. Springer has seen a 72-point dip at home from last year. Danny Jensen has watched his home-slugging drop by 30 points, though your mileage may vary on what the expectations for Danny Jensen — a 28-year-old backup catcher with a .222 career average — should be. Bo Bichette has seen a jump in power, but that’s mostly due to his penchant for hitting the ball the opposite way, where he’s seen a 30-point rise in slugging on fly balls he hits to right field, though Rogers Centre hasn’t been any more forgiving to right field either.

It might have gotten into Guerrero’s head. In April, Guerrero pulled 21 percent of his fly balls. In July it was 8.3 (though in five August games at home that’s jumped back to 20 percent).

To simplify all this, Guerrero has been the same hitter he’s always been, at least in how he goes about doing his job. And on the road, he’s the same near-MVP candidate you probably picked pretty high in your fantasy draft (139 wRC+). But at home, he’s been basically Dominic Smith. Which isn’t what the Jays were hinging their postseason hopes on.

It’s hard to connect that moving the walls in has made it harder to hit for power for those who call the park home, but baseball is strange that way. It appears to have bitten Vladito and the Jays right in the ass.

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