Why Muñoz is poised for an even bigger year in 2023

March 16th, 2023

PEORIA, Ariz. -- Add Andrés Muñoz to the list of prominent Mariners pitchers who plan to attack hitters with a new pitch this season. The bigger adjustment for Seattle’s highest-leverage reliever, however, will be to the pitch timer installed for the 2023 season.

Muñoz toyed with both on Thursday when facing opposing hitters for the first time since offseason surgery on his right foot. In one inning against the Padres during a “B” game on the Peoria Sports Complex backfields, he threw 16 pitches (10 strikes), gave up one walk and one single and struck out one, while his Seattle teammates tied the Giants 0-0 in the "A" game.

His command was admittedly -- and expectedly -- shaky as he hurled his new sinker and managed the timer, which will be for 15 seconds with the bases empty and 20 with a runner on, per MLB’s new rules.

“A little bit better every time,” said Muñoz, who has been throwing live BP to Mariners hitters. “I feel like today, I was thinking too much about the pitch clock, and I started to worry too much about it. I started to get faster every time.”

Data isn’t publicly available on time in between pitches, but Mariners officials said that Muñoz was the slowest on the team in 2022. Part of that was by delivery, part by design. Muñoz said that the pain in his foot, which began roughly one month into last season, prompted him to regularly circle the mound after each pitch.

“Right now, I’m just trying to figure out what I have to do to be more aggressive with every pitch, even if I have to do it faster,” Muñoz said. “Because normally, the time that I take off the mound and working a little bit was more like giving time to the ankle and trying to get energy again to throw the next pitch.”

There are no mechanical adjustments needed for the 6-foot-2, 222-pound lumbering force -- just rhythm and tempo, which probably won’t be effectively adjustable until high-leverage moments manifest during the regular season. Cactus League games have been much easier for starters to acclimate.

The fastball adjustment has been even more deliberate. Despite Muñoz possessing a four-seamer that averaged 100.2 mph, the second fastest in MLB, opposing hitters had a .388 batting average and .500 slugging percentage against it, per Statcast, leading him to trust it less. The slider limited hitters to a .126 batting average and .176 slugging percentage with a 50.8% whiff rate, third-best among relievers (min. 200 sliders thrown).

As Statcast shows, Muñoz was throwing his slider almost four times as often as his four-seamer by season's end.

He had more success with the heater as the season went along, but the predictability of its movement became a liability, including a few key moments during the American League Division Series against Houston -- notably against Alex Bregman.

“Not just the Astros, but other teams, too. They got used to my fastball,” Muñoz said. “And that's why I threw a lot of sliders. ... I know that I don’t have a lot of time throwing it, but I know that they’re going to study a lot about it -- my slider, my fastball -- but as soon as they see something different, they have to start thinking about it."

Teammates in live BP have suggested that Muñoz’s new profile is similar to the two- and four-seam combo that has made Luis Castillo one of the game’s best fastball arms. That combo was almost exclusively what helped Castillo blank the Blue Jays during Game 1 of the AL Wild Card Series, and Muñoz possesses even more velocity.

“I talk a lot with [Castillo] about that, and he’s taught me a lot of things about that pitch,” Muñoz said. “I feel with time, I’m going to get more used to it and get more comfortable with it and be able to throw it in all counts like my slider and my fastball. I’ve just got to give it time with more reps.”

And to be clear, Muñoz isn’t ditching the four-seamer.

“It’s still my favorite pitch,” he said with a smile.

Shaking out kinks is what Spring Training is all about, though Muñoz’s situation is perhaps more pronounced given the proximity to Opening Day -- still, he and the Mariners maintain that he’ll be ready. More important than the sinker or pitch timer is that he said his foot felt fully healthy.

If he puts it all together, Muñoz could be poised for an even bigger year than in 2022, when he emerged as one of MLB’s best relievers.