Yermín Mercedes struggling to reach top speeds

Back before Tony La Russa blew up Yermín Mercedes’ blowing-up of a Willians Astudillo eephus pitch into a national controversy, Chris Kamka tweeted out something that was initially amusing, and then alarming:

“Ho ho!” I thought. “A pitch speed of 47.1!”


“Oh, no!” I thought. “Nothing faster than 92.2 mph!”

From that point on, I began watching how Mercedes fared against decent fastballs, and sure enough, he isn’t turning them around. I ran a Baseball Savant search on White Sox average exit velocities against fastballs 94 mph and faster, all of which qualify as above average velocity. Mercedes is at the bottom, at least among players with anything resembling a substantial sample size.

BatterTotalAvg. EV
Yasmani Grandal1197.5
Luis Robert1095.9
Andrew Vaughn1395.8
Jake Lamb1295.4
Yoán Moncada2092.6
Adam Eaton1991.0
Nick Madrigal2690.5
José Abreu2590.2
Tim Anderson2189.9
Zack Collins1288.2
Billy Hamilton1284.7
Leury García1784.5
Nick Williams281.9
Danny Mendick470.0

Now, you might look at Mercedes’ team-leading sample of batted balls and say that some of the unusual action he generates with his two-strike swing may result in laughably low EVs that drag down the average, and that’s true to a certain extent. But he’s also not a threat to put strong fastballs in play in the air. Of these 29 batted balls, only four have an exit velocity 95 mph or higher, and all of them are grounders to the left side.

This makes him pretty easy for certain pitchers to set up, because most 94+ mph fastball strikes are either staying on the ground or going foul.

If a pitcher with average-or-better velocity wants to get ahead in the count when facing Mercedes, he can. If he wants to get back in the count, he can. There are a lot of ways to get to two strikes against him, and as a result, he ends up seeing the greatest percentage of two-strike pitches of any White Sox regular. Yoán Moncada has him beat in terms of sheer number, but the exit velocity on two-strike pitches suggest it’s the result of a discerning eye.

  • Moncada: 143 pitches of 603 (23.7%), 95.3 mph avg. EV
  • Mercedes: 126 pitchers of 480 (26.3%), 83.7 mph avg. EV

As’s Mike Petriello noted this morning, it’s a terrible time for any hitter to fall into two-strike counts, because hitters are faring worse than ever before with two strikes, at least on record. The league context of .159/.236/.256 is what makes Nick Madrigal’s .296/.321/.432 line with two strikes such a marvel.

In this context, Mercedes’ .245/.297/.300 line with two strikes looks respectable. But that also took a dip in May:

  • April: .341/.383/.477
  • May: .203/.261/.203

The adjustment to Mercedes has resulted in a weird dynamic. As you might expect from the guy with baseball’s fourth-highest chase rate, he’s seeing more than twice as many two-strike sliders in May (32.2%) than he was in April (15.2%). But he’s only seeing a miniscule increase in breaking balls total because he’s also seeing more fastballs. Per his Statcast page:

  • April: 53.3% fastballs, 36.2% breaking
  • May: 54.6% fastballs, 37.0% breaking

They’ve pretty much stopped throwing him changeups because he can crush lower velocities. Instead, pitchers are using fastballs to pad the count, and breaking balls when they don’t need the strike. Compare the progression of the fastball percentages he’s seeing to how the league is adjusting to Andrew Vaughn:

Yermín MercedesApril43.740.943.8
Yermin MercedesMay58.157.453.8
Andrew VaughnApril67.353.347.6
Andrew VaughnMay44.941.533.3

Mercedes is easy to both set up and knock down in this form, which is why he’s batting .212/.282/.313 since the start of May. In order for Mercedes to reverse his slide to return to doing damage, something’s gotta give. He either needs to be more selective with sliders, or he has to punish pitchers for challenging him with fastballs. Otherwise, he’s going to have short at-bats that end in groundouts, longer at-bats that end in weak or no contact, and little in between.

This is why Jake Lamb’s sudden surge is so handy, because the White Sox don’t have to send Mercedes out there to DH in the spot behind José Abreu every day if the matchup is rough. It’d be a little bit of a bummer if the Yermínator hype dissolved into an ordinary lefty-mashing platoon bat after just one month, but it’d be worse if the Sox didn’t have other options to buy time until Eloy Jiménez can return. The White Sox are scheduled to see two righties — Casey Mize and Spencer Turnbull — to open this four-game series against Detroit, which could generate an early indication of whether Tony La Russa has similar changes in mind.

UPDATE: Well, Mercedes and Lamb are both in tonight’s lineup because Andrew Vaughn hit the COVID-19 injured list. Gavin Sheets is taking Vaughn’s place on the 26-man roster.

“In compliance with MLB’s existing COVID-19 protocols, Andrew Vaughn has been placed on the injured list,” said Rick Hahn, White Sox senior vice president/general manager. “Andrew is currently asymptomatic and our hope is that, similar to our other IL placements of this nature, he will return shortly to the active roster. At this time, no other players on the roster are impacted.”

Vaughn missed Monday’s doubleheader with an alleged bout of allergies, so here’s hoping that’s factored into the asymptomatic claim.

(Photo by Frank Jansky/Icon Sportswire)

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Jim Margalus
Jim Margalus

Writing about the White Sox for a 16th season, first here, then at South Side Sox, and now here again. Let’s talk curling.

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This is great Jim. Thanks. I knew Yermin was swinging at a ton of low and outside pitches, which we have seen with many of young hitters when they first come up. It seems like Yermin could benefit from a conversation with Abreu about catching up with velocity. I know Jose was struggling early in the season with fastballs, but he has seemed to right the ship a bit on that, so maybe he has some pointers for Yermin.


It seems like Mercedes pops to the right side quite a bit too.


Yermin is starting at DH. Lamb in LF. No Vaughn


probably because against righties, Vaughn has:

55 wRC+

As Cirensica

Gavin Sheets called up!

Andrew Vaughn to the IL. Turns out Vaughn’s allergy was of a Coviditis19 variety.


I had a similar type of reaction. Felt like a bad cold or allergies more than anything.

Anyway, great analysis, Jim. I’m sure many were wondering if Yermin is just slumping or if the league is figuring him out.

I think the Sox should trade him when Eloy comes back. They have too many DH/1B types already and he is not playable in the field.


I could be wrong, but I doubt Yermin has much value. One hot month from a not highly rated prospect DH probably doesn’t carry much value across the league.


We’ll always have April.


it seems like yermin’s good bat-to-ball skills are dragging down his exit velocities when paired with his lack of plate discipline. he’s putting some balls in play that would simply be whiffs for most other players. early in the season, it felt like those were all turning into duck snorts. now, it seems like they’re weak pop-ups and ground balls.

i think there’s some potential here, given his contact skills and high top-end exit velocity, but he’s chasing himself out of at-bats a lot lately. it feels as though he’s in self-preservation mode at all times.


So if Sheets plays, I believe that will be the 10th different player to see time in the outfield this year for the Sox (Engel should hopefully be #11 soon, Eloy #12 some time in the distant future). If you had told me in March that the Sox would be on their 12th-best OF option by June, I would have assumed we were 10+ games back in the standings.


Didn’t think anything of the decision to call up Sheets until you mentioned Engel. What else does he need to do in Charlotte to be ready for the bigs again?


Has he still not played many games in a row yet due to off days and weather? Maybe they want to make sure the hammy can handle an extended run before bringing him back since i would guess he would play almost everyday.


Working on his defense


Good luck to Gavin. May he not be Andy Wilkins.


I noticed last night at the game that Mercedes seems to have a real upper cut to his swing right now. He misses, fouls off or grounds out with it. I’d like to see him level it out and go to the opposite field to break out of his slump. Does he have the discipline to do it?