August 10, 2026 — EVERETT, Wash.: Seattle Mariners Executive Vice President & General Manager of Baseball Operations Justin Hollander announced today that left-handed pitcher Mason Peters has been promoted to the High-A Everett AquaSox from the Single-A Inland Empire 66ers.
A native of Waco, Texas, the 22-year-old Peters was drafted by the Mariners in the fourth round (No. 122 overall) of the 2025 MLB First-Year Player Draft out of Dallas Baptist University. Currently ranked as the Mariners’ No. 13 prospect per MLB Pipeline, Peters made his professional debut with the 66ers in April as a member of their Opening Day roster.
Featuring a fastball that sits between 93-96 MPH, a sweeping slider, and a curveball that plays in the upper-70s, Peters has found immense levels of success in his first post-collegiate campaign. Across 14 starts with Inland Empire, — eight of which have been scoreless outings — he has pitched to a 1-0 record with a 1.43 earned run average across 50.1 innings. Peters has also struck out 68 batters in comparison to just 12 walks, holding opposing hitters to a 0.85 WHIP and a slim .175 batting average against.
Standout performances for Peters with the 66ers include four innings of no-hit, shutout baseball against the Ontario Tower Buzzers on April 10. In that outing, Peters struck out nine and walked only one. He also dazzled during another shutout outing June 12 — this time against the Rancho Cucamonga Quakes — where he spun five innings and struck out six while walking none and allowing only two hits.
Peters is currently scheduled to make his AquaSox debut Thursday, August 13, against the Spokane Indians. First pitch for the game is scheduled for 12:05 p.m. at Everett Memorial Stadium as the AquaSox are hosting a Camp Day matinee. Tickets are available for purchase at AquaSox.com, and Peters’ appearance is subject to change at any time.
ABOUT THE EVERETT AQUASOX: The Everett AquaSox are the defending 2025 Northwest League Champions and serve as the High-A affiliate of the Seattle Mariners. Established in 1984, the club has been affiliated with the Mariners since adopting the AquaSox name in 1995. For the latest updates on the 2026 season — including community initiatives and appearances by Webbly — follow the Frogs on Facebook, X (formerly Twitter), Instagram, YouTube, and TikTok, or visit AquaSox.com. Season ticket packages, group outings, and picnic experiences are available now by calling (425) 258-3673 or by visiting the AquaSox Front Office at 3802 Broadway.
ABOUT MINOR LEAGUE BASEBALL: Minor League Baseball consists of 120 teams across four classification levels (Single-A, High-A, Double-A and Triple-A) that are affiliated with Major League Baseball’s 30 teams. Fans flock to MiLB games to see baseball’s future stars and experience the affordable family-friendly entertainment that has been a staple of MiLB since 1901. For more information, visit MiLB.com and follow MiLB on Facebook, Instagram and Twitter.