When the Athletics traded their star closer Mason Miller last July, they knew they were doing so purely for the future. That future is not yet here, and nor is it close. But the present is making for some uncomfortable viewing.
The San Diego Padres had landed one of the sport’s most electric pitchers, a closer who regularly touched 103 mph, struck out hitters at absurd rates and remained under team control through 2029. San Diego was chasing a championship and had just added a weapon unlike any other reliever in the game – not just a dominant arm, but a dominant arm for many years. The Athletics, meanwhile, were doing what the Athletics always seem to do: trading away a star.
Less than a year later, the deal still has the potential to become a win for the A’s. But watching Miller dominate in a Padres uniform makes it impossible not to wince a little.
Miller Is The Best In The Game
Miller has been exactly what the Padres thought he could become, if not better. After arriving in San Diego at the 2025 trade deadline, he posted a 0.77 ERA with 45 strikeouts in 23.1 innings for the Padres to close out the year – combining his work in Sacramento and San Diego, he finished 2025 with a 2.63 ERA, 22 saves and 104 strikeouts in 60 appearances.
He has somehow gotten even better in 2026.
Earlier this year, Miller set a Padres franchise record with a scoreless streak that stretched more than 34 innings, also ranking as the eighth-longest streak in MLB history by a reliever. By the time the Athletics faced him for the first time since the trade, he had established himself as the best closer in baseball. Heading into their series finale against the Los Angeles Dodgers, Miller has pitched in 32 games, converted all 21 of his save opportunities, and given up only 14 hits and 13 walks in 34.0 innings for a 0.79 ERA, a 0.79 WHIP, a .122 batting average against, and at a rate of as-near-as-is two strikeouts per inning. He is untouchable.
Players like Miller do not come along often. The Athletics gave up on him for four more chances at greatness, or at least goodness. But one of them has already gone wrong.
High Price For Miller
The Padres’ offer was substantial enough to make even a controllable superstar available. The A’s sent Miller and JP Sears to San Diego in exchange for shortstop Leo De Vries and pitching prospects Braden Nett, Henry Baez and Eduarniel Núñez – the first, third, thirteenth and seventh-best prospects in the Padres’ farm system respectively. The centrepiece was De Vries, who at the time ranked as MLB Pipeline’s No. 3 overall prospect, and now sits even higher in second place.
In exchange for Miller, then, the Athletics received one of the most highly regarded prospects in all of baseball, plus three additional arms with legitimate upside. De Vries has continued to hit in the upper minors, spending much of 2026 at Double-A and hitting .281/.374/.423 with 28 steals while still only 19 years of age. Even if he gets moved off of the shortstop position in the long run, his upside is very, very high.
Relievers are volatile, especially ones who throw this hard. Miller had already dealt with arm injuries earlier in his career, and the Athletics were not close to contention. By the time they realistically expected to compete, Miller would have been much closer to free agency. Trading a reliever at peak value for a potential franchise shortstop is the type of move analytically minded front offices will always aim for. The logic is there, and De Vries could pay dividends for a decade or more yet.
There is, however, a vast yawning chasm of difference between understanding a trade, and enjoying it.
Let’s Not Act Like It Augurs Well Here
Miller was not just effective as an A. He was marketable. He was one of the game’s best already and was electric in the process, as a good closer should always be.
If De Vries develops into the superstar many scouts expect, the Athletics could eventually emerge as the winner – or at least something approaching even – and if any of Nett, Núñez or Baez had become useful major leaguers as well, the Athletics may ultimately look very smart. But in contrast to De Vries’s encouraging development, the arms acquired in the deal are not panning out as well. Nett gave up 15 walks in 9.2 innings at the Triple-A level and is in need of a hard reset, Baez has a 7.11 ERA at Double-A, and Nunez was traded to the Baltimore Orioles for cash. At this point, none figure to get even to the level of Sears.
Right now, Mason Miller is doing exactly what the Padres hoped he would do when they paid such a steep price. He is shutting down games, blowing away hitters and helping a contender chase a championship. Patience is key and justified, but it is hardly fun to have. For the A’s, watching Mason Miller pitch hurts.
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