Joe Jacques Shocks MLB: Red Sox Reliever’s Rapid Rise & Game-Saving Performance Explained

KEY TAKEAWAYS • Seattle Mariners acquire left-handed reliever Joe Jacques from the Los Angeles Dodgers in exchange for right-hander Will Klein, per multiple club sources. • Jacques adds a second southpaw option behind closer Andrés Muñoz, addressing a glaring bullpen imbalance. • The Shrewsbury, N.J. native posted a 2.31 ERA with Triple-A Oklahoma City and possesses two remaining minor-league options, giving Seattle roster flexibility. TRADE DETAILS The Mariners finalized a one-for-one swap on Monday night, sending 26-year-old fireballer Will Klein to Los Angeles for Jacques, a 30-year-old left-hander who debuted with Boston in 2023. Reports of the agreement surfaced first via MLB Trade Rumors and were confirmed by both organizations Tuesday morning. WHY SEATTLE MADE THE MOVE • Lefty shortage: Prior to the deal, Seattle’s bullpen featured only one healthy left-handed reliever. • Ground-ball machine: Jacques’ sinker averages 93 mph and generated a 57 percent ground-ball rate in Triple-A this season. • Cost control: He is pre-arbitration eligible through 2026 and still has two options, letting manager Scott Servais shuttle him if match-ups dictate. PLAYER PROFILE • Name: Joseph Jacques • B/T: L/L • Height/Weight: 6-4, 230 • 2025 Triple-A stats: 23.1 IP, 2.31 ERA, 0.99 WHIP, 26 K, 6 BB • MLB career: 5.40 ERA over 21.2 innings with Boston and Arizona in 2023-24. WHAT JACQUES BRINGS 1. Sinker-slider combo that neutralizes left-handed bats (.184 BAA in Triple-A). 2. Improved splitter unveiled this spring to attack right-handers late in counts. 3. Poise in leverage; opponents hit .167 with runners in scoring position for Oklahoma City. IMPACT ON THE MARINERS’ ROSTER – Jacques is expected to replace Eduard Bazardo, who was optioned after allowing four runs Sunday. – Seattle now sports a more balanced bullpen: RHPs Muñoz, Brash, Santos; LHPs Saucedo, Jacques. – The club still owns the fourth-best bullpen ERA (3.09) in MLB but ranks 25th in left-on-left match-up usage; Jacques should boost that metric. ABOUT WILL KLEIN The 2020 third-round pick heads to a Dodgers system renowned for pitcher development. Klein averages 98 mph with his fastball but struggled with command (14.2 percent walk rate). The move frees a 40-man slot in Seattle and gives Los Angeles a high-upside arm to polish. LOOKING AHEAD Jacques is likely to join the Mariners in time for their weekend series against the AL-West-leading Rangers. If he translates his Triple-A success, Seattle may have quietly solved its most pressing bullpen need and fortified its playoff push without surrendering a top-10 prospect.