What can we expect from Andres Munoz out of the Mariners bullpen in 2023?

Division Series - Houston Astros v Seattle Mariners - Game Three
Division Series - Houston Astros v Seattle Mariners - Game Three / Steph Chambers/GettyImages

During the 2020 season, the Mariners had been playing Austin Nola at catcher. He was having a career year, and had been playing quite well since debuting for the Mariners in 2019 (.280/.351/.476, 125 OPS+). With Tom Murphy on the roster and Cal Raleigh recently being drafted, the Mariners decided to ship out Nola with Austin Adams and Dan Altavilla. In one of the best trades the Mariners have ever made, they received Ty France, Taylor Trammell, Luis Torrens, and Andres Munoz from the Padres.

With Luis Torrens failing to succeed in Seattle and the verdict on Taylor Trammell still in the air, the Mariners have found two incredible pieces that should be around for quite a while. Ty France will be around through at least 2025, and it would be interesting to see if the Mariners are able to sign him to an extension before then. Meanwhile, Andres Munoz has already been signed to an extension, inking a potential 7YR/$31.5M deal. (Last three years are a 3YR/$24M club option)

Andres Munoz is going to have a dominant 2023 season for the Mariners

Just one year into the deal, it already looks like the Mariners have struck gold with Munoz. He was incredible in 2022, owning one of the best sliders not just in Seattle, but the entirety of baseball. After embracing the pitch and throwing it nearly 65% of the time, opponents hit just .126 with a .176 SLG against it in 2022. It was actually the 11th-best PITCH IN ALL OF BASEBALL, including starters, with a run value of -20.

It's not just a slider either. He had the second-highest average fastball velocity in 2022, registering a mark of 100.2 mph, behind only Jhoan Duran (100.8). He was oddly unlucky with the pitch, as hitters had a BA against of .338, but an expected BA against of just .266.

It's a long-winded way to setup the question of what we can expect next year. I wanted to put all of this info in here because i think we might be seeing the beginning of one of those dominant runs that relievers get on. This isn't just going to be a flash in the pan, where a reliever shines for a couple of years and then fades away. No, this looks more like the beginning of an incredible career.

Andres Munoz


K Rate (K)

BB Rate (BB)




13.3 (96)

2.1 (15)


2023 - rough


11.3 (65)

3.88 (22)


2023 - great


14.2 (104)

1.77 (13)


Predicting reliever stats is an entirely different exercise than other positions. I could try and predict ERA or FIP, but I don't think those are as indicative of the type of year that a reliever has. We've seen it with Diego Castillo in 2022. People think he had an awful year, although by taking a look at his appearances you can see that a couple of bad innings greatly inflated his ERA.

If Munoz indeed does have a league-leading nasty slider, there is no reason why he couldn't replicate last year's numbers. There's a part of me that wonders what would happen if he could adjust his fastball, and how devastating that could make him. We should be able to tell how he's doing by the K and BB rates. BABIP will play a part, but with a fastball touching 102-103 and that slider, he does see a lot of weak contact.

Oh, and he's healthy now, too. He underwent foot surgery, hopefully correcting an injury that bothered him during the season, although details about when he got it are a bit hard to find and nail down. I think that a healthy Munoz is one of the best 3-5 relievers in all of baseball, and that his 2023 stats are going to end up reflecting that fact.