What’s Up With Corbin Carroll? A Dive Into the Swing and Struggles of the Diamondbacks Star

Carroll was the unanimous NL Rookie of the Year and top five in NL MVP voting in 2023. Now, the Diamondbacks star is searching for answers.

PHOENIX, ARIZONA - MAY 13: Corbin Carroll #7 of the Arizona Diamondbacks warms up in the on deck circle during the game against the Cincinnati Reds at Chase Field on May 13, 2024 in Phoenix, Arizona. The Diamondbacks defeated the Reds 6-5. (Photo by Chris Coduto/Getty Images)

Baseball can be a cruel sport. Even the most talented players on earth, like Corbin Carroll of the Arizona Diamondbacks, can endure stretches where they struggle to recapture what makes them so good. That’s especially true of an art form like hitting, which can go awry from a simple shift in mechanics or timing.

On June 29 of the 2023 season, Carroll left a game against the Tampa Bay Rays with his right shoulder hanging limp by his side after a swing. It was a particularly concerning sight because it happened to be the same shoulder the Diamondbacks’ star had surgically repaired after suffering a labrum tear and posterior capsular avulsion when he was a minor leaguer in 2021.

While there’s a stark contrast in Carroll’s production since tweaking his shoulder last season, he returned to the lineup after missing just a couple games. And, despite exiting another game a week later with discomfort yet again, he returned to the lineup the very next day and even played in the All-Star Game the next week.

MRIs continued to come back clean, and Carroll, as well as the Diamondbacks brass, have remained adamant that his shoulder is in a good spot. The fact that both Carroll and the D-backs have not mentioned the shoulder at all as it pertains to the outfielder’s struggles prompted me to dive deeper into his swing mechanics and batted ball data to try to put the pieces together. There were a few things that jumped out immediately.

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Struggles at the Top

Carrolls massive drop-off in production against fastballs has been well documented at this point, but his bat speed is actually improved over last season, as Yahoo’s Jordan Shusterman detailed in a very informative piece on Carroll’s struggles earlier this month.

While Carroll never was much of a high ball hitter, he has not even been competitive against four-seamers at the top of the zone this season. Carroll posted an OPS over 1.000 on four-seamers 30 inches high and above in 2023. So far this season, Carroll has an OPS under .400 against such pitches.

Such a dramatic drop-off almost always coincides with a mechanical issue, especially when dealing with a young hitter who has not seen a drop off in bat speed and the exit velocities would back that up.

Against fastballs, Carroll has maintained an average exit velocity of 88 mph, just a couple decimal points lower than his 2023 average. Against breaking balls, his average exit velocity is a five mph lower than last year. Both path and posture issues may be leading to his inability to cover the top of the zone as well as breaking balls so far this season.

Swing Mechanics

Shusterman’s piece included quotes from both Carroll and Diamondbacks coaches who identified excessive “counter-rotating,” or simply turning too far inward towards the catcher in his load, as an explanation for his inconsistent bat angle and challenges with the heater.

That would absolutely make sense as the more a hitter turns inward, the longer his body has to travel to get his barrel to the point of contact, which could result in a hitter feeling stuck, effectively making it more difficult to catch up to fastballs. That said, there may be more involved in the struggles than just the counter-rotating.

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A more visually apparent discrepancy in Carroll’s swing is his stride. He has always gained a lot of ground with his leg kick, but he may be over-striding now, and the open-side angle provides a great look at this.

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The difference at foot strike is eye-opening. Carroll gains so much ground that the bottom of his back foot actually comes off of the ground before the barrel gets moving. The angle of his back knee stands out as well.

Because of how twitchy and explosive Carroll is, he’s still able to generate bat speed from a position that undoubtedly saps impact, as he is hardly able to use the ground as much as he did with his weight already shifted forward and only the instep of his back foot touching the ground.

Another result of the weight shift forward prior to his hands launching is the barrel getting stuck behind him. Much like the counter-rotation Carroll mentioned, this could also impact path and timing. Using the same video, you can see the angle of Carroll’s bat being slightly more vertical with his 2023 swing and not quite as wrapped around him.

His barrel also moves forward in sync with his rotation in his old swing, while you may notice his belt buckle already facing the pitcher while his barrel is still behind him this year. Both differences are likely to contribute to a flatter path. When the bat angle becomes too horizontal, the window for quality contact shrinks. The result is more hard hit baseballs that are at undesirable launch angles on both ends of the spectrum.

In addition to making it more difficult to pull the ball, Carroll’s hands getting so far behind his body may result in him feeling like he needs to decide earlier, which can negatively impact swing decisions.

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2023Pop-up: 11%Hard-Hit LA: 13.5°Pull: 35%Chase: 16.5%
2024Pop-up: 23%Hard-Hit LA: 8.5°Pull: 27%Chase: 22%
Against Four-Seam Fastballs

The discrepancies become even more evident when you sort the batted ball data by pitches 30 inches high and above, and based on how Carroll is being pitched, opposing teams have picked up on this. A quick look at the spray charts against fastballs 30 inches and above likely only makes pitchers more confident that they can beat the All-Star outfielder with their heater.

Through his first 50 games of 2024, Carroll has seen a 6% uptick in four-seam fastballs along with a 5% increase in fastballs located in the top third of the strike zone. He has seen similar increases in fastballs on the inner half and with two strikes.

This will only compound the feeling of a hitter needing to cheat for velocity, which will not only impact his fastball chase rates, but it leaves him more susceptible to expanding on sharp breaking balls as well.

Carroll has seen a 13% jump in chase rate against sliders, making contact further out front on average than 2023, resulting in a 20% increase in ground ball rates against such pitches. With his average fastball contact being deeper and slider contact further out in front, this is an example of how hitters can feel “in between,” compounding their struggles.

How Concerned Should We Be?

As the sample size of poor performance increases, the level of concern will of course coincide, but it’s also important to recognize how high of a bar the unanimous National League Rookie of the Year set for himself as he went on to help lead the Diamondbacks to just their second World Series appearance in franchise history and first in over 20 years.

Carroll was Just Baseball’s No. 1 overall prospect in 2023 for good reason. The industry called the 8-year, $111 million pre-arb extension the team handed him ahead of the 2023 season a slam-dunk, which is still entirely valid; the 23-year-old is a face of the franchise talent.

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Frankly, I am not sure Carroll has really ever faced any on-field adversity in his life, dating back far before his historic 2023 rookie campaign. He hit .450 in his high school career with 22 home runs in four varsity seasons at Seattle’s Lakeside High School and dominated at every major summer event in front of scouts before being selected 16th overall by the Diamondbacks in the 2019 MLB Draft.

He immediately hit the ground running as an 18-year-old in professional baseball, posting an OPS of .896 between the Complex and short season ball during the 2019 season. COVID wiped out 2020 and then the aforementioned shoulder injury ended Carroll’s season at just seven games in 2021. The injury stung a little extra because of how ridiculous Carroll’s start to the season was, going 10-for-23 in High-A with five extra base hits.

Then 21-years old, Carroll returned healthy in 2022 and didn’t miss a beat despite being assigned straight to Double-A. At this point, he had played just seven regular season games from the end of 2019 to the beginning of 2022 and had essentially skipped over both Low-A and High-A, making up for lost time in a way that the game had not seen in a long time from a high schooler.

Despite limited reps at the lower levels, the upper levels were light work for Carroll, hitting .307/.425/.610 in 93 games between Double-A and Triple-A before earning a call up to the big leagues, were he put up an OPS of .830 in 32 games.

This is a longwinded way of saying that Carroll may have never been in a position to make any major adjustments at the plate in his professional career. It’s hard to pinpoint exactly what may have led to Carroll’s mechanics going awry. Maybe there was some subconscious compensation for an uncomfortable shoulder, or maybe the shoulder had nothing to do with anything. It’s far from uncommon for even the most talented of hitters to slowly slip into a bad habit over time, making it harder to feel the difference in swing mechanics.

Throughout Carroll’s prolonged slump, we have not seen any mechanical adjustments of significance aside from the “counter-rotating” aspect, which is relatively minor and seems to be more of a feel thing than a major discrepancy that may show on video. It may sound backwards, but that is more encouraging than Carroll tinkering with different setups and pre-swing moves, searching to no avail.

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Teams are extremely cautious when it comes to having their star hitters make adjustments because it can sometimes take the player further away from where they originally were. When hitting has come so natural to certain players for so long, it can become increasingly difficult to retrace your steps.

Carroll is a rare baseball talent with bat speed you rarely see from a player of his frame paired with a great feel the barrel and strike zone. He’s one of the game’s most athletic players and is easily the most explosive, pound-for-pound.

All of these things can allow a hitter to get away with a bit more inefficiencies than others, which could also be how some of Carroll’s swing components got away from him slowly over time before reaching the point he is at now.

Between his physical talent and well-documented makeup, anything short of a turnaround from Carroll would be shocking. When that happens is a different story, and clearly he and the Diamondbacks are thinking small before exploring a more dramatic change.

Re-patterning pre-swing moves, especially when they are as loud as Carroll’s can be difficult, but it almost surely is a matter of time before the star outfielder returns to form.