MLB deadline blockbuster: A’s trade star closer Mason Miller for elite prospect
AI-generated summary reviewed by our newsroom.
- A's traded Mason Miller and JP Sears to Padres for top prospect Leo De Vries.
- De Vries headlines a return package including three high-upside pitching prospects.
- Padres may convert Miller back to starter as they chase Dodgers in NL West race.
The Athletics traded 2024 All-Star closer Mason Miller and starting pitcher JP Sears to the San Diego Padres for a package highlighted by MLB’s No. 3 overall prospect, the West Sacramento-based team confirmed Thursday.
The Padres’ top prospect, 18-year-old switch-hitting shortstop Leo De Vries headlined the group of four prospects the A’s received in exchange for their sole All-Star selection last year.
De Vries was the top international prospect in the 2024 signing class, receiving a $4.2 million bonus from the Padres when he agreed to join the system out of the Dominican Republic in January 2024. Since his signing, De Vries has performed well in both A and High-A ball, currently holding a .767 on-base plus slugging percentage and eight home runs in 82 games of his age 18 season.
De Vries is a true five-tool player with an advanced eye and approach to the plate, according to his scouting report on MLB.com.
The A’s also received three of the Padres top pitching prospects: Braden Nett (No. 3 ranked within the Padres system, per MLB Pipelin), Henry Baez (No. 13) and Eduarniel Nuñez (No. 17).
What did the A’s give up?
On top of being a former All-Star, Miller, 26, has four seasons of team-control following the 2025 season, making him extremely valuable as a long term piece.
While he debuted in MLB as a starter in 2023, Miller earned his spot as the team’s closer with his 28-save, fourth-place American League Rookie of the Year campaign in 2024.
A report by the Athletic on Wednesday said the Padres (60-49) were looking to potentially turn Miller back into a starter to boost their chances of overtaking the Los Angeles Dodgers (63-46) for the National League West crown.
Although Miller’s ERA this season of 3.76 is more than a point higher than his 2.49 mark last year, the A’s closer was already well on his way to pass last year’s save total with 20 on 23 attempts entering the deadline.
Miller likely would’ve had his chance at No. 21 on Wednesday after the A’s carried a 5-3 lead into the ninth inning, going on to win 5-4, but Manager Mark Kotsay said postgame he was “unavailable” for non-injury reasons. The decision immediately prompted speculation that a trade was imminent ahead of Thursday’s 3 p.m. deadline.
Sears, 29, has been one of the most consistent starters for the Athletics since he joined the club in 2022. He threw 32 games while holding mid-4 ERAs each of the last two seasons and had thrown 111 innings in 22 starts so far in 2025.
While Sears never posted a winning record in a season for the A’s, and holds a 4.95 ERA in 2025, his consistency could help the Padres in various inning-eating roles.
Who else did the A’s get?
Nett, 23, throws a high-90s fastball and a signature cutter that have served him well in the minors leagues as of late. In 17 Double-A starts this season, the righty holds a 3.39 ERA and has fanned 86 in 74 innings.
Baez, 22 years old and standing at 6-foot-3, has also shined in Double-A this season with a slurve-esque curveball, stellar split-change and mid-90s fastball. In 20 starts, he holds a 1.96 ERA but has struck out less than a batter per inning pitched.
A devastating slider and fastball that has touched 101-mph headlines Nuñez’s repertoire. The right-handed reliever held a combined 2.83 ERA from his stints in Double-A and Triple-A this season.
In a four-game stint with the Padres at the big-league sellers, Nuñez threw 4 2/3 innings, surrendering two runs and striking out two.
While Kotsay said Monday that the term “sellers” wasn’t an accurate description of the A’s, they have already traded two of their biggest names in the rumor mill.
Starters Luis Severino and Jeffrey Springs as well as third baseman Miguel Andujar have also had their names thrown around, as the league prepares for the 3 p.m. deadline.
This story was originally published July 31, 2025 at 10:02 AM.
