Andrés Muñoz has been one of baseball’s best relievers over the past three seasons. During that span, the Seattle Mariners right-hander has a 2.49 ERA, a 2.68 FIP, and a 34.7% strikeout rate over 176 games, comprising 173 1/3 innings. Acquired from the San Diego Padres as part of a seven-player trade in August 2020, Muñoz missed the entirety of that year and all but the final game of the 2021 season recovering from Tommy John surgery. He posted a 2.12 ERA and 22 saves in the just-completed campaign, both career bests. Muñoz’s M.O. on the mound is power. Per Statcast, his four-seamer averaged 98.4 mph this season, while his two-seamer averaged 97.5 mph and his slider 87.6 mph. The velocity — but not his overall effectiveness — was actually down from the previous two years. In 2023, Muñoz’s four-seamer averaged 99.2 mph, and in 2022 it averaged 100.2 mph. His slider is his most-thrown pitch, and its speed has also ticked down a tad, although not to his detriment. With a caveat that his slider wasn’t always sharp this season, it elicited a .138 BAA, a .191 wOBA, and a 48.5% whiff rate. The 25-year-old native of Los Mochis, Mexico sat down to talk about his repertoire and approach at Fenway Park earlier this year.
David Laurila: The last time we talked, you told me that you’re a bit of pitching nerd. To what extent?
Andrés Muñoz: “Yes. We have all this information, but I don’t want to put it all in my head. I try to make it simple. At the same time, I want to know where to attack the hitters. Where are their weaknesses? I use that. Like everybody, I like to have the information, but by the time I am on the mound, I’m not thinking about all the information. I’m thinking more about, ‘OK, where am I supposed to throw the pitch?’ I feel like that is the best thing for me, to have a plan for every hitter.”
Laurila: What about your pitch profiles and how you can optimize them? I assume you pay attention to that when you’re not on a game mound.
Muñoz: “The coaches here have helped me a lot with that. Sometimes you don’t know things. We’re obviously not perfect; we fail sometimes. I feel like the more that we practice, the more that we are in the bullpen throwing and repeating the things that give you that muscle memory you need to perform the way that you want to perform… but yes, for example, the slider. It works better when it goes side-to-side instead of down. That is something we have to work on in the bullpen. We make sure that things are going in the way that you want.”
Laurila: Can you manipulate your slider so that it gets either more depth or more side-to-side movement?
Muñoz: “Sometimes I can. Every day is different. Sometimes we feel that we can’t do that, but the more you practice the easier it is to go there and make it move [to the] side, or make it move down.”
Laurila: When did you start being able to do that?
Muñoz: “Probably this year. Before it was more down. I didn’t even think about the movement. But again, when I’m in the game I don’t think about anything. I’m just throwing my pitches. But my subconscious, in one part of my mind, I already know what to do. Sometimes things just don’t work like you want them to.”
Laurila: Have you changed the way you throw your slider?
Muñoz: “Yes. I changed the grip. I threw it differently in 2022. For some reason, after the injury to my shoulder [in April 2023] it started to change a little bit. I wasn’t able to locate the slider that good. So we changed the grip. There is more in that one, but it’s harder to locate.”
Laurila: The one you’re throwing now is harder to locate?
Muñoz: “Yes, because it moves more. That is why sometimes you see me miss too much with the slider. It moves a lot. Sometimes we think we are throwing it the same, but it moves more and is harder to maintain the same location.”
Laurila: You throw your slider pretty hard…
Muñoz: “I try to throw it as hard as I can. I feel like that has been working for me. I don’t like to reduce intensity on my pitches. When I don’t get ahead in the count, on the next pitch I try to throw it harder to remind me that… when I throw in the bullpen before the game, I try to throw as hard as I can, just to get that same feeling. That way it doesn’t surprise me, like, ‘Oh, I was just warming up and not throwing as hard as I can’ and then I go to the game and it’s another intensity.”
Laurila: What was your repertoire when you first came to pro ball?
Muñoz: “[Four-seam] fastballs and sliders.”
Laurila: Now you have a two-seamer as well. When did you start throwing that?
Muñoz: “I started to practice the two-seam at the end of 2022. I didn’t do it because I wanted to throw it in the game; I just did it because they told me that it would help me a little bit with my four-seam. Knowing the difference between the two-seam and the fastball… you’re trying to throw it at the same spot, but the ball moves differently. In 2023 was the first time that I started throwing it in games. It worked good, and this year I came in with those three pitches.”
Laurila: Do you get much ride on your four-seam?
Muñoz: “No, I don’t. It’s more because of the speed that it looks like I have ride on it. And then the two-seam gets a little bit of sink. It goes exactly like a fastball and then drops at the last moment. That is what gets me groundballs. I don’t use the two-seam to strike guys out; I use it for groundballs.”
Laurila: Have you ever had a curveball or a changeup?
Muñoz: “No. I’ve tried a curveball, but it never worked for me. I tried to use a cutter too, but it goes more like a slider for me. I’ve never really tried a changeup.”
Laurila: Not even in the minors?
Muñoz: “I threw a changeup one time when I was with San Diego. They told me to throw it like a fastball, so I gripped it like a changeup, threw it, and it went 96. That is not a changeup. Maybe it’s something about my mechanics or the way that I throw the ball, but it didn’t work for me.”
Laurila: The reliever for the Twins throws a splitter in the high-90s…
Muñoz: “Yes. Jhoan Duran. They call it a ‘splinker.’ Hopefully I can learn something like that in the future, but right now I am just concentrating on making my pitches the best that I can. The offseason is a time to work on things, so maybe one day. That was my mentality when I tried throwing a cutter in practice, but after two weeks I decided it didn’t work.”
Laurila: Circling back to your shoulder injury, did your arm slot change at all?
Muñoz: “Yes. My arm slot started to get more down. That was why I started to throw more two-seams. For some reason the two-seam works better when your arm is a little bit down. But right now I am just trying to make it simple.. I don’t think about mechanics. I don’t think about anything. I just try to be athletic.”
Laurila: Any final thoughts on pitching?
Muñoz: “My mentality is to attack everybody. I’m going to go as hard as I can. If I face the best hitter on the team. and then the next guy comes up, I’m going to do the same thing. Everybody here is good, so you can’t go easier on anyone because they aren’t the best. You have to be the same guy out there and…
