The Reason A's Zack Gelof is Struggling

Baseball is hard. That's why, when Oakland A's second baseman Zack Gelof came up to the big leagues and had immediate success last season, it was pretty impressive. This season has been more of a struggle through the team's first 21 games.

Gelof has played in all 21 contests thus far, and through 89 plate appearances, the 24-year-old is batting just .188 (15-for-80) with seven walks that have led to a .261 OBP. He's tacked on two homers and three stolen bases, but of his 15 hits, just five have been for extra bases.

It's obviously not the start that he wanted, but in looking over some pitch data, it looks as though he could break out of this early season slump with a couple of adjustments.

Over at Baseball Savant, they tell you what each hitter around baseball is batting against each pitch type, and how many of those pitches they're seeing. The thing that stands out about Gelof's early-season performance is that he is struggling against fastballs, a type of pitch that he crushed last season.

In his rookie campaign, Gelof hit .324 with an expected batting average (xBA) of .284. This year he's hitting just .219 with an xBA of .243. His numbers against breaking balls and changeups has stayed relatively the same from year to year.

So fastballs. Not four-seamers, however. It's the sinkers that are giving him more of an issue. Last year he was 23-for-59 against sinkers, good for a .390 average with a .542 slug. This year he's 0-for-10 to begin the season, and he's whiffing on them 40.9% of the time. When he's made contact, his exit velocity on sinkers is roughly in line with where it was last year, going from 86.6 miles per hour to 85.9, but the adjustment that needs to be made is with his launch angle.

In 2023, his launch angle on sinkers was just two degrees, but it got the job done. This year, it's at -17, so he's hitting it right into the ground. His overall launch angle this season is also down from 11.8 degrees to 5.1 degrees.

Part of the reason for this type of contact is because he's topping balls at a pretty high rate, 52.9%. Last year that was at 30.7%.

So what all of this tells us is that the problem is not his timing, because he's hitting the ball just as hard as he was last season. Instead, it's his swing path being slightly off.

The good news is, if he can figure out how to drive the ball instead of getting on top of it, then the rest of the stats seem to indicate a return to what he showed last season. The hard part here is that pitchers can continue to tinker on their end to make that process insanely difficult, giving Gelof another moving target to aim for.