The A’s Sent Mason Miller To The Padres For An Elite Prospect

There are always huge, unexpected deals on the day of the trade deadline, and the A’s and Padres have given us a whopper. Star reliever Mason Miller is heading to San Diego along with lefty starter JP Sears in exchange for a package of prospects centered around Leo De Vries.

Miller is the hardest throwing pitcher in baseball. His fastball averages 101.1 mph and has reached as high 104.1 mph this season. In 103 career appearances spanning three seasons and 136 2/3 innings, he has a 3.16 ERA with only 81 hits allowed, and he has struck out 201 of the 539 batters he has faced. This season, he has a 3.76 ERA, but his peripheral statistics are much better, including his 2.86 FIP, 39.1% strikeout rate, and .159 batting average against.

While other relievers might have better surface stats, perhaps none in baseball was more coveted. The 26-year-old flamethrower has unmatched velocity and is only earning $765,000 this season. He will reach arbitration eligibility for the first time this offseason, and won’t become a free agent until 2030.

It’s not a surprise to see the A’s as deadline sellers. They’re in last place in the American League West with a 48-63 record, but it still had to have been difficult to part with a young strikeout machine with four full years of team control remaining—which means he would’ve stayed with the team until after their planned move to Las Vegas.

With Miller added to the mix, San Diego has arguably the most fearsome bullpen in baseball. They already had three All-Star relievers: Jason Adam, Adrian Morejon, and Robert Suarez. Miller wasn’t an All-Star in 2025, but he earned the honor in 2024. They also have Jeremiah Estrada, whose 66 strikeouts are 7th in MLB among relievers.

The 60-49 Padres are three games behind the Dodgers in the National League West, and they’re taking a big swing to reach the playoffs. Should they succeed, their plethora of elite short relief pitchers will make them a team no one wants to face.

Sears is a valuable asset as well, though not nearly up to Miller’s level. He’s a durable arm with a 4.95 ERA this year. He started 32 games in both 2023 and 2024, and he has made 22 starts so far in 2025.

Prying Miller loose from the A’s wasn’t cheap. De Vries is only 18, but he’s already one of the very best prospects in baseball. MLB Pipeline ranked him third overall in their midseason update. He was widely considered the best player available in the 2024 class of international amateur free agents, signing with the Padres for a $4.2 million bonus. The switch-hitting shortstop is batting .245/.357/.410 in High-A, where he’s 4.3 years younger than the average player at that level.

The three other prospects headed to the A’s in the deal are pitchers Henry Baez, Braden Nett, and Eduarniel Nunez. None of them appear on top 100 prospects lists, but all are seen as possible contributors in the major leagues someday.

The real prize is De Vries, without whom it’s unlikely that the A’s would’ve sent Miller to San Diego. Now that he’s there, it’ll make the Padres that much more formidable in the late innings, including in the postseason.

Source: https://www.forbes.com/sites/danepstein/2025/07/31/the-as-sent-mason-miller-to-the-padres-for-an-elite-prospect/