Mariners closer Andrés Muñoz was slipping even before Yankees pitch-tipping scheme

When it comes to the Seattle Mariners bullpen, Andrés Muñoz has been the best arm so far this season followed by Matt Brash and then Gabe Speier. So it was somewhat ironic that all three contributed towards the most devastating loss of the season, on Thursday in the road series finale against the New York Yankees.

Muñoz's outing was the most alarming, as he took a season-high 31 pitches to get through the bottom of the ninth, allowing two runs to send the game to extra innings. By that point the writing was on the wall, as the Yankees completed their stunning comeback from a five-run deficit in the eighth inning to win 6-5 in the bottom of the 10th.

At the heart of Muñoz's disastrous performance was the Yankees picking up on him tipping his pitches and putting their plan into action once they had two runners on base. As per Chris Kirschner and Brendan Kuty of The Athletic (subscription required), when the righty threw his slider the man on second base would wave his arms in a circle to signal to the batter.

Kirschner and Kuty added the man on first base for the Yankees would also signal, but in any event Cal Raleigh soon realised the hosts knew that Muñoz was tipping. Raleigh said: "He was tipping it every time at second base. Obviously, they weren’t making it very discreet, I guess is the word. It’s part of the game. It’s our job. We should have known about that going into the series. That made it really hard there at the end."

Not a scandal no matter how aggrieved Mariners fans may feel

Whatever people want to think of the ethics in all this, it is still ultimately on Muñoz and it's particularly worrying that the potential is there to eliminate his slider, which is easily his best pitch and at one point was pretty much untouchable. As SoDo Mojo's Jason Wang wrote towards the end of May, he was throwing the slider 49.1 percent of the time at that point and it was producing a .047 opposing team batting average and 53.4 whiff rate.

What adds considerable cause for concern is that the two-time All-Star was having some issues even before Thursday's collapse against the Yankees. Since producing a sparkling 0.00 ERA through his first 24 appearances of the 2025 season, he now has a 4.76 ERA in his past 12 outings.

It's also noticeable that a player who usually strikes out players at such a high rate has dried up in this area of late, with just five Ks in his six most recent games including none versus the Bronx Bombers. This leads to the question of if the Yankees are the only team to have figured Muñoz out.

Andrés Muñoz still excellent overall, BUT ........

To be clear, none of this is about downplaying what Muñoz has achieved so far this season, with him currently projected to have career bests in WAR, ERA, ERA+ and saves. However, it's going to be extremely interesting to watch how he responds/performs in the coming weeks.

One look at the 26-year-old's Baseball Savant page tells you there's still more than enough to like, highlighted by ranking in the 98th percentile for breaking run value and 97th percentile for fastball velo. However, the Mariners must consider helping him make some adjustments moving forward, to guard against similar results like the one at Yankee stadium.