San Diego Padres Arbitration Decisions & Projections: Mason Miller

[Joshua Hutter]

The San Diego Padres had an All-Star bullpen in 2025, and it got even better at the trade deadline, when Mason Miller was acquired from the Athletics on July 31 along with JP Sears. Miller immediately elevated the late-game advantage that the Padres already had and helped to mask a lot of the issues within the starting rotation. Following the injury to Jason Adam, most pitching staffs would have felt stretched, but this addition made that fallout much less noticeable than it should have been, which says a lot when you lose an All-Star reliever.  

Originally drafted in the third round by the Athletics in 2021, Mason Miller had an outstanding limited season with the Padres:

• 22 Games 
• 23 1/3 Innings Pitched
• 0.77 ERA
• 1.12 FIP
• 54.2 K%
• 12.0 BB%
• 0.39 HR/9
• 1.1 FanGraphs' WAR (fWAR)

Stretch the scope out to his entire season and his numbers take a slight dip, which makes one wonder what could have been if he had been on the Padres for the entire season:

• 60 Games
• 61 2/3 Innings Pitched
• 2.63 ERA
• 2.23 FIP
• 44.4 K%
• 12.0 BB%
• 0.73 HR/9
• 2.0 fWAR

Mason Miller, 27, is entering his first arbitration-eligible season and is estimated to earn around $3.4 million in 2026. Given his dominant closer/late-inning role and elite strikeout rate this past season, the Padres must weigh whether to style him for just the arbitration year or seek a multi-year extension to lock in cost certainty. This decision is going to be of high strategic importance for the club’s long-term bullpen architecture. 

In the playoffs against the Chicago Cubs, Miller was unhittable:

• 2 Games
• 2 2/3 Innings Pitched
• 0.00 ERA
• 88.9 K% (including striking out eight consecutive batters, tying the MLB postseason record)

The right-hander was everything you could have hoped for when he came over at the trade deadline. He throws a 100-plus mph fastball and a sweeping slider, causing many mismatches late in games. What stands out is not just his raw velocity (he threw an average of 101.2 MPH on his fastball in 2025), but how he balances his limited arsenal. His slider gets lost behind the thunderbolts he throws with his four-seamer, and yet, that pitch was his best this season:

• 48.4% active spin on the slider
• 54.6 Whiff% on the slider (third-best among all pitches thrown in MLB)
• 52.4 K% on the slider (third-best among all pitches thrown)

Miller was traded for with both a win-now and a win-later mentality. Closer Robert Suarez faced uncertainty down the stretch, with a player option to opt-out at the end of the season (which he has exercised). Miller is an easy fit to slide in and be his replacement in the closer role, having fulfilled that position with the Athletics before; he saved 70 games over two and a half seasons before being traded. The Padres got both younger and more affordable with this move while keeping the bullpen essentially intact despite losing the league leader in saves in 2025.

With all that being said, is that what the Padres actually brought him in for? The Padres need starting pitching; Yu Darvish just had elbow surgery and will be out for the 2026 season, Michael King and Dylan Cease are free agents, Joe Musgrove is returning from a year-long layoff, and Nick Pivetta is the only reliable starter returning from last season. There have already been rumors that Miller might move out of the bullpen and become a starting pitcher. He had six starts in 2024, throwing 24 ⅓ innings and finishing with a 3.70 ERA. He won’t be able to continue to throw his 100-plus mph fastball on a regular basis, but he has already shown that his slider is the actual pitch that elevates him to elite-level status. He primarily only threw those two pitches in 2025, having also thrown a changeup, but he would most likely need to start expanding his arsenal to effectively manage batting orders multiple times through.

So, the real question for the Padres becomes: Where do you put him? This could be answered with any additional moves that the team makes this offseason, though his role could also determine the contract he gets in arbitration or in an extension (starters always make more than relievers).

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