Three Potential Mason Miller Replacements for the A's This Winter

As the A's worked through their rebuild, Mason Miller was one of the players that emerged and established himself quickly in 2023, even in a rookie season that was cut short due to injury. That injury also had the A's move him to the bullpen in order to keep him more healthy. Two years later, that decision would end up making him trade bait.

In 2024, still technically his rookie season, Miller turned himself into one of the best closers in all of baseball, holding a 2.49 ERA with 28 saves across 65 innings of work. He was also named an All Star for the first time.

In 2025, he struggled a touch in the month of May, along with the rest of the A's and their bullpen. The hard-throwing righty gave up 10 earned runs in just 8 2/3 innings that month, ballooning his ERA to 10.38 in the month and 5.49 on the year. He'd still finish with a 3.76 with the A's by the time they traded him, and put up a 0.77 ERA over two months with San Diego.

Miller ended up with a 2.63 ERA on the year, right in line with where he was as a breakout rookie star. On the eve of the deadline, Miller questioned his own value to a rebuilding club like the A's, whom he'd racked up just 38 1/3 innings with through the end of July.

At the Trade Deadline the A's decided to move him and JP Sears, grabbing one of the top prospects in baseball in Leo De Vries, whom the Athletics are hoping turns into a huge star in Las Vegas for them. The thought process here being that De Vries and the pitching prospects they brought in will help the roster in a few areas, instead of as a lockdown closer for a 76-win club.

The thought process makes sense from the A's point of view. Still, with Miller now in San Diego, they'll need to find a new full-time closer.

Over the final two months of the season, the A's went with a closer by committee and ranked second in MLB in ERA with a 2.99 during that span. Michael Kelly (2), Sean Newcomb (2), Tyler Ferguson (1) and Osvaldo Bido (1) all earned a save, but the leader in the clubhouse was...

Hogan Harris

From the beginning of August through the end of the season, Harris ended up with a 1-0 record, four saves, with a 1.16 ERA (3.01 FIP) and a 0.81 WHIP. He has the demeanor to lock things down in the ninth, with A's manager Mark Kotsay describing it as a "---- You" mentality when he's on the mound.

In other words, he's not going to let one bad pitch or one bad outing derail him from reaching his goals.

One worry with Harris would be that while he was terrific during that stretch, he did have just a .179 BABIP against and held a 90.9% left on base rate, which is extremely high. The league average was 71.8% for relief pitchers over the course of the year.

That all said, the 28-year-old left-hander has been fairly consistent the past two seasons, posting ERAs of 2.86 and 3.20, which would be perfectly acceptable as the ninth inning guy for the club. He could also end up being the main lefty option for the A's in the bullpen, and locking him into the ninth inning may not be the direction they're after.

Luke Weaver

Luke Weaver has been a potential target for the A's that we've been talking about for a couple of months now. The right-hander seems like the perfect candidate for the A's to scoop up in free agency this winter, given his solid track record the past two seasons, but also the questions that surround him following his injury.

When he landed on the IL on June 3 with a hamstring strain, Weaver held a 1.05 ERA over 25 2/3 innings of work. He was pitching extremely well, especially considering the Yankees' deep postseason run the year before.

When he returned on June 20, he posted a 5.31 ERA the rest of the way across 39 innings. This included an ERA of 7.15 in July and a 9.64 in September. That all said, he has still put together a 3.21 ERA the past two seasons combined with a 29.5% strikeout rate and a 7.8% walk rate.

Over that span, Jeff Hoffman has been a similar reliever (31.3% strikeout, 7.8% walk with a 3.28 ERA), and he ended up signing a three-year, $33 million deal with the Toronto Blue Jays last offseason. Maybe that's a reason to stay away from Weaver, who has 12 career saves, as Hoffman is not expected to be the primary closer for the Jays in 2026.

Jack Perkins

One way or another, it just feels as though hard-throwing Jack Perkins will end up in the A's bullpen at some point in 2026. If the A's add a veteran starting pitcher to the rotation, that would likely move Perkins out of the starting five, barring an injury. The projected starters right now are Luis Severino, Jeffrey Springs, Jacob Lopez, Luis Morales and Jack Perkins.

The A's would love to keep him as a starting pitcher if they can, but if they find another suitable starting option, moving him to the bullpen makes plenty of sense—especially considering that it's the same path that Mason MIller took with a similar profile.

Perkins is too good to not be on the roster in some fashion, and he has the arsenal to be a ninth inning guy. He made his MLB debut in 2025 working as a long reliever at first, and in those initial 19 2/3 innings, he held s 2.75 ERA with a .159 batting average against and a 0.92 WHIP. As a starter, he held a 5.68 ERA in 19 innings with a .225 BAA and a 1.42 WHIP.

Now this is just a guess, but if Perkins is to be named the closer in 2026, we think that it may happen later in the season. Perhaps it's after Harris or Weaver struggles. Or maybe he actually starts the season in the rotation, but after Gage Jump or Braden Nett makes it to the big leagues, they push him out of the rotation, and he ends up working the latter innings, eventually taking over the ninth.