The Seattle Mariners have lost an important member of their coaching staff, as Triple-A hitting coach Shawn O’Malley has reportedly joined the Washington Nationals.
The 37-year-old, who is originally from Washington state, was listed as the Nationals’ new Assistant Hitting Coach in a post shared Tuesday. The move marks a significant step up for O’Malley, transitioning from Seattle’s minor league system to a major league coaching role in Washington, D.C.
O’Malley departs Seattle after a successful post-playing career that steadily advanced through the organization. Most recently, he served as the hitting coach for the Tacoma Rainiers, the Mariners’ Triple-A affiliate, where he made a strong impact.
From Player to Coach
Drafted in the fifth round by the Tampa Bay Rays in 2006, O’Malley made his MLB debut with the Los Angeles Angels in 2014. He later spent parts of two seasons with the Mariners, appearing in 113 games for Seattle between 2015 and 2016.
Over three major league seasons, the switch-hitting utility player appeared in 124 games, batting .231 with three home runs and 11 stolen bases. Known for his defensive versatility, O’Malley had a memorable moment in 2016 when he hit a three-run home run on the same night Ken Griffey Jr.’s number was retired, helping Seattle secure a crucial win during a playoff push.
After retiring as a player, O’Malley began coaching in 2020, joining the Mariners as a minor league hitting instructor and steadily rising through the ranks.
Impact in Seattle’s System
O’Malley’s time with Tacoma was especially successful. In 2025, he earned the Mariners’ Dave Henderson Minor League Staff Member of the Year award after helping guide the Rainiers to a second-half Pacific Coast League championship.
Under his leadership, Tacoma’s offense ranked among the league’s best, placing near the top in hits, RBIs, walks, and on-base percentage.
He also played a key role in developing several Mariners players and prospects, including Dominic Canzone, Cole Young, and Harry Ford. Canzone, who was recalled to Seattle in June, went on to hit .300 with 11 home runs. O’Malley emphasized collaboration in that process, focusing on blending past strengths with adjustments suited to the player’s goals.
O’Malley’s departure is part of a broader offseason shift for the Mariners following their 2025 success. Third base coach Kristopher Negrón left to become the Pittsburgh Pirates’ bench coach, bullpen coach Tony Arnerich accepted the same role with the Cleveland Guardians, and assistant general manager Andy McKay also joined Cleveland as field coordinator.