Can Eury Pérez reach ace potential while getting so few grounders?

Eury Pérez is following closely in the footsteps of Sandy Alcantara. The Miami Marlins ace recognized Pérez's potential when he was still a prospect. Since then, Alcantara has eagerly advised his fellow Dominican on how to navigate his career, on and off the field. Fittingly, he was the one who delivered the news of Pérez's call-up last May.

Pérez is gifted enough to someday match or even surpass Alcantara's achievements, but he'll have to arrive at those results in a much different way.

Alcantara's signature pitch has been his sinker. Pairing elite velocity with nasty movement, it's the key to how he induces hundreds of groundballs every season. According to FanGraphs, the MLB groundball rate annually hovers around 43%; Alcantara has exceeded that in each of his six Marlins campaigns, averaging a 50.6 GB% since 2018. As permanently inscribed on his wrist, the groundball double play is Alcantara's best friend (no offense, Eury).

 

 

 

 

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Meanwhile, Pérez did not use a single sinker as a rookie in 2023. He throws just as hard as Alcantara, but that's where their fastball similarities end. "Baby Goat" found immediate success in Miami despite a bizarre batted ball profile.

Pérez's groundball rate was only 25.4%, per FanGraphs. Among all pitchers who completed at least 90 innings in the majors last season, he ranked dead last.

Should the Marlins be worried?

Generally, a pitcher's ideal outcome for any plate appearance is a strikeout. But when that is not attainable, a grounder is a solid alternative.

During the 2023 season, MLB hitters collectively posted a .336 batting average and .560 slugging percentage on batted balls, according to Baseball Savant. For batted balls that stayed on the ground, their production plummeted to a .248 batting average and .273 slugging percentage. Compared to other batted ball types, the defense behind you is more likely to convert grounders into outs, and the risk of allowing extra-base hits is practically non-existent. 

Eury Pérez induced grounders at a pretty normal frequency while ascending through the minor leagues. He has posted a 40.0 GB% in 191 ⅔ career MiLB innings pitched. In his two separate stints with Double-A Pensacola last season (totaling 36.2 IP), he had a 45.9 GB%, which was even above the Southern League average.

Although Pérez hit the ground running (pun intended), solidifying his place in the Marlins starting rotation as a 20-year-old, opponents were constantly launching his pitches. Only one of his 19 Marlins starts included a groundball rate above 50% and only two topped 40%. He even had an outing with zero grounders allowed (Sept. 14 vs. Brewers).

Not only was Pérez's groundball rate the lowest of any MLB starter with a comparable workload in 2023: it was on pace to be the third-lowest single-season mark for a qualified starter in the entire Sports Info Solutions era (2002-present). FanGraphs uses SIS for GB%.

The table below shows all of the qualified starter seasons from 2002-2023 that had grounders account for less than one-third of batted balls allowed:

The first thing I noticed was the prevalence of Chris Young. The All-Star right-hander turned World Series-winning executive has been the only pitcher over the last two-plus decades to maintain a sub-Eury GB% throughout a qualified season. All four qualified seasons of his career comfortably fit within this screenshot.

Coincidentally, Young (listed at 6'10") is one of very few pitchers in MLB history who was even taller than the 6'8" Pérez. I don't think that is particularly relevant to this analysis, though. Pérez does not leverage his immense stature the way you might expect—by vertical release height, he is only slightly above the league average.

Pérez posted an excellent 72 ERA- last season (100 represents average). Several other pitchers here have shown it's possible to pair that performance with extreme flyball tendencies: Justin Verlander in 2018 (AL Cy Young award runner-up), Max Scherzer in 2016 (NL Cy Young winner), Jered Weaver in 2011 (AL Cy Young runner-up), Ted Lilly in 2009 and Jarrod Washburn in 2002.

Collectively, however, this group is unremarkable. The median ERA- of their seasons is just 96. There's seemingly no correlation between suppressing grounders and suppressing runs.

I don't believe that Eury Pérez was doing this by design, nor should he if he aspires to fill Sandy Alcantara's shoes in 2024. There was a full-run gap between his ERA (3.15) and FIP (4.11). He was too susceptible to "barrels" (10.7 Barrel% vs. the 6.9% MLB average). Some good fortune was on his side. That's why every projection system sees him taking a step back as a sophomore.   

With that being said, projection systems are blind to the possibility of players making adjustments. There is an obvious one for Pérez to consider: incorporating more changeups.

Pérez established himself as a phenomenal prospect in part due to how advanced his changeup was. As explained to Fish On First, though, he has seldom used it in The Show so far because he was getting acclimated to throwing MLB baseballs; in the Southern League, he had been using an experimental "tacky" ball instead. His changeup command lacked consistency in 2023, often missing his spots by too much to entice opponents to swing.

From Alex Chamberlain's pitch leaderboard, here are the groundball rates that hitters had against Pérez when plate appearances ended with different pitch types:

• Four-seam fastball—15.5 GB% (129 batted ball events)
• Slider—37.3 GB% (67 BBE)
• Curveball—42.9 GB% (21 BBE)
• Changeup—62.5 GB% (16 BBE)

Lance Brozdowski reports that Pérez's changeup usage was approximately 14% in the minors compared to 9.8% as a Marlin. If he regains trust in his offspeed offering, that should lead to more innocuous grounders and a more well-rounded batted ball diet moving forward.

Pérez must also be careful with where he locates his four-seamer. It has exceptional spin that plays well up in the strike zone, but when it lands in a hittable area, major leaguers have the reaction time to catch up to high-90s velo and do serious damage against it. Four-seamers are responsible for 10 of the 15 home runs he surrendered during his rookie campaign.

Is there anything else that you think could be contributing to Eury's batted ball distribution? Let me know in the comments!