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How to Repair a Mercedes

The lovable, 28-year-old Yerminator finished May with a .628 OPS; can he bounce back?

Baltimore Orioles v Chicago White Sox
Keep it Yermín: Mercedes will need some guidance and encouragement to bust out of his May slump.
Ron Vesely/Getty Images

Yermin Mercedes was one of the best — you know what? Let’s just lean into it —

— the best story of April, to open the 2021 season:

  • Your American League Rookie of the Month.
  • A historic 8-for-8 start, making Mercedes the first player in the modern era (since 1900) to begin a season with eight consecutive hits.
  • A temperamental 1.113 OPS for Mercedes’ first month of his first big-league season.
  • Yermin’s homer on April 8 versus Kansas City flew 485 feet, the second-longest home run hit by a White Sox in the Statcast era, inspirational enough for Fabulous Freddie’s to charge $4.85 for a chimichurri-topped Yerminator burger.

The White Sox selected Mercedes in the minor league Rule 5 draft, snatching him from the talons of the Baltimore Orioles. Since the onset of his career 10 years ago, Mercedes had been able to mash at every level of the minors and various independent leagues, finishing his minor league career with a respectable .857 OPS.

He very well could have been the 27th man on the 2020 shortened-season roster, but was overlooked for Edwin Encarnación, who was signed to a why-not, one-year deal for big money late in the offseason.

Despite Mercedes mashing hell out of the ball in the truncated 2020 spring training, preference for the backup-backup catcher role was given to Zack Collins — perhaps a bit more of a catcher than Mercedes, but that’s an article for another day.

Being a power bat who lacked adroitness in a defensive position was an obstacle in Mercedes’ road to the major leagues, and finally — a global pandemic. In 2021 at 28 years old, Mercedes finally found himself in an everyday starter’s role at designated hitter for his first full major league season, as Eloy Jimenez’s injury meant that Andrew Vaughn would have to learn a new position in left field.

And with a large personality to match his loud bat, the White Sox fan base became enamored with Yermin, and he returned as much of its love as he could, with seven multi-hit games in April and an unforgettable five hits on Opening Day in Anaheim. It was Mercedes himself who approved the Yerminator nickname, recording a commercial just as fun as his culminating April OPS of 1.113: “Come with me if you want to win.”

And then May 17 happened.

So what exactly happened on May 17?

The check engine light

Yermín’s April start sparked plenty of discourse in the baseball world on sustainability, and dissections on his approach at the plate. It was noted that Mercedes was an especially good two-strike hitter (the White Sox are generally a fantastic two-strike hitting team), with a simplified swing and eliminated leg kick when the count fell out of his favor. “See the ball, hit the ball,” was Yermín’s simple answer when asked about his success.

It wasn’t far-fetched to expect Mercedes to regress, at least somewhat. It’s worth pointing out that in the stretch between May 1 and 16, Mercedes went 10-41 (.241) in 13 games played, with no home runs, six RBIs, and four walks drawn. Not horrible numbers, but pale in comparison to that torrential April, and probably not worthy of being in the fourth or fifth spot in a lineup.

And, oh yeah, we were gonna talk about May 17.

It was a blowout game versus the Twins, where Rocco Baldelli sent position player-pitcher extraordinaire Willians Astudillo to eat an inning and lob some pitches to get the game over with. Astudillo was having some trouble locating his eephus for strikes, nor was he able to lure Mercedes into a whiff trap.

And so, the count fell to 3-0. And the rest is history.

Enter Tony La Russa, stage left. A handful of us noticed that La Russa, the requisite Hall-of-Fame-baseball-person, was shaking his head in disgust as Mercedes rounded third base, as Yermín apparently defied La Russa for swinging on 3-0, and would probably offer some predictably bad comments to the media. Indeed, in a postgame press conference, La Russa mentioned that Mercedes was “clueless,” and perhaps ominously, mentioned that the rookie would face some kind of “discipline” from within the family, whatever the hell that means.

Looking past the horrible optics of an already-established (Hall of Fame, remember?) manager being blissfully unaware that a rookie like Mercedes would need to pad his stats to secure an ample payday once arbitration rolls around, the comments coming out of the now-controversy somehow got worse.

The next day, on May 18, Mercedes was in the lineup and went 2-for-4, but Twins reliever Tyler Duffey threw behind Mercedes, resulting in the ejection of both Duffey and Baldelli. La Russa commented that “he had no problem” with the way the Twins handled the situation, and perhaps this is the “discipline” he’d say Mercedes would face. La Russa went so far as to offer qualifiers about the situation: The pitch was a sinker, but if it had been a fastball, or up toward the head, then he would have had a problem with it.

Let’s take a quick inventory of what that looks like: public humiliation, and the threat — and advocacy — of physical assault. And that’s just what we’re seeing externally, as fans.

A mechanic’s diagnosis: Did Tony cause Yermín’s slump?

Short answer, no.

Yermín had been slumping before the May 17 incident, but recency bias leads us to believe the slump started after. However, it would be permissive to assume Tony didn’t at least exacerbate things.

I like to think of it this way: Imagine your house is on fire, and you’re holding a blowtorch. The obvious conclusion would be that the blowtorch caused the fire, right? But in reality, the house has been burning for a short while; you’ve seen the smoke, but have been too distracted to notice the flames have been spreading from room to room.

The blowtorch goes on to call your house “clueless,” and that it will “face discipline from within the family” later.

La Russa’s comments may not have singlehandedly made Mercedes slump, but they sure as hell didn’t help. In May, Mercedes slashed .221/.292/.326 over 106 plate appearances; specifically from May 17 to 31, he slashed .204/.279/.333. La Russa could have been a fire engine, but instead chose to be a blowtorch.

It was refreshing to see that Mercedes had the support of his teammates, in tandem with most of the sensical side of the baseball analytics world, but some comments telling him he lacked mental toughness need to be addressed.

Citing a lack of mental toughness on the part of a player isn’t a great look — it’s the rough equivalent of blaming a house for burning down instead of finding the deeper cause of who or what set the house on fire. It’s lazy at best, and why sports psychology even exists, to study and solve why slumps happen. Players are human, and sure, it’s normal for a rookie to fall back down, as so expertly explained to me ad nauseam via Twitter.

This discourse can certainly devolve into hierarchical dynamics quickly, but without getting too off-course, anyone reading this can relate to how a bad boss — specifically one that hangs their workers out to dry without remorse — can further exacerbate the work environment and make it, do I dare say? Toxic.

Routine maintenance

Here’s where I throw a bunch of numbers at you and attempt to make sense of Mercedes’ slump via some screenshots. A brief analysis of Mercedes’ pitch mix tracking shows that he has problems hitting breaking balls: Into Thursday, he’s got a .205 average (on 301 pitches thrown into Thursday) against those pitches, compared to a .364 average against fastballs (433 thrown), and a really robust .400 average (73 thrown) against off-speed stuff.

His Whiff% is especially high on breaking balls, at 24.1%, due to a lot of chasing. The obvious solution here would be something like, “Hey, Yermín, try to hit a curveball better,” but it’s a bit more complex than that, as these numbers can be noisy.

If you look at his pitch breakdown for both April and May, you’ll find that he’s always had trouble with breaking stuff. However, his strong numbers on hitting against velocity have also dropped significantly: in April, he was thrown 176 fastballs, for a ridiculously good .571 average; in May, he was thrown 251 fastballs for a .253 average. Yikes.

A breakdown of pitch types Mercedes saw in April, May, and a sliver of June.
Baseball Savant

So yes, pitchers are adapting to him; other teams have done their homework, and that’s objectively fair. You can see a nosedive in Mercedes’ wOBA against all pitch types; however, going back to him especially having trouble with breaking pitches, check below for a correlation in rise in pitches outside the zone, and a drastic drop in his wOBA.


Pitchers are also now throwing very carefully to Mercedes. Take this heat map from April, where pitch location is a little more spread through the bottom of the zone:


And this one from May shows that pitches are now heavily located away.

We’ll get into the frequency of pop flies in a minute, but related to this, we’re noticing a dip in sweet-spot percentage — how often a hitter produces a batted-ball event in the launch angle sweet-spot zone of 8-32 degrees, which just takes launch angle into consideration. Yermín has been floundering below the league average for a while now.


Anecdotally, I’ve noticed an uptick on pop-ups especially on x-2 counts, and the data supports that. If you’ve noticed that he’s having difficulty squaring the ball, you’re correct. Goodness, look at all these popped-up infield flies. And yes, he’s also pulling the ball less.


Mercedes is seeing significantly more fastballs going into June — as well as breaking pitches, resulting in more chase, having difficulty squaring the ball, and a concerning uptick in infield pop-ups. Turning fastballs around again would be a priority, knowing that pitchers will now live in the outer part of the zone. Pitchers are also being less reckless against him, and maybe that’s the greatest form of flattery.

Despite all this, Mercedes is still a good hitter, as his historical numbers have shown, but with this downturn in production, his profile is becoming stock across the board.

So, how do you repair a Mercedes? (Wait a minute. Is he a house? Is he a car? Nah, he’s a person!) The short and unscientific answer is that he’ll need to adapt. He’ll need to turn whatever scouting reports opponents have on him upside-down, and also listen to team leaders like Tim Anderson, Lucas Giolito, and José Abreu to rediscover his confidence. Again, Tony may not have caused Yermin’s slump, but he hasn’t been much help to bring him out of it.

To go back to my exhausted metaphor one more time, it’s always possible to repair a burning house, just maybe keep this time keep the flamethrower away.


This analysis was done yesterday afternoon, before Yermín’s game-winner last night. And the good news is that his GWRBI single was a turned-around slider, located inside. He’s been having trouble hitting pitches located away, especially breaking pitches, so hopefully this is a sign of good things to come.

Hopefully it’s as simple as “see the ball, hit the ball” again.

Thanks to Michael Ajeto (@dysthmikey) for help with this piece.