MIAMI – The Miami Marlins today announced the club has signed left-handed relief pitcher John King to a one-year Major League contract. In a corresponding move, the Marlins designated left-handed pitcher Josh Simpson for assignment.
King, 31, posted a 2-1 record and 4.66 ERA (25 ER/48.1 IP) in 51 relief appearances with the St. Louis Cardinals in 2025, with 28 strikeouts and 14 walks. The 6-foot-2 left-hander, who ranked second in the Cardinals’ bullpen with a 2.61 BB/9 ratio (min. 45.0 IP) and third in appearances, also finished his third season with St. Louis ranked in MLB’s 98th percentile in ground ball percentage (60.0) and 91st percentile in barrel percentage (5.0), per Baseball Savant.
The Laredo, Texas, native enjoyed a career-best 2.85 ERA (19 ER/60.0 IP) in 2024, also setting career highs in appearances (56) and innings pitched during his first full season with the Cardinals after joining the club as a mid-season acquisition in July 2023. He also posted a career-best 2.10 BB/9 ratio during the campaign, walking just 14 batters and ranking in baseball’s 87th percentile with a 5.6 walk percentage, per Baseball Savant.
Since becoming one of five Major League players to make their MLB debut in 2020 despite not appearing in a game above the High-A level, King has compiled a 16-14 record and 3.80 ERA (107 ER/253.1 IP), 68 walks, and 165 strikeouts in 214 relief appearances between Texas (2020-23) and St. Louis (2023-25).
King was originally by Texas in the 10th round (314th overall) of the 2017 First-Year Player Draft out of the University of Houston. He elected to undergo “Tommy John” surgery shortly after being drafted and made his professional debut in August 2018. By 2021, King was rated with the “Best Change-Up” in the Rangers’ system, per Baseball America.
Simpson, 28, made his Major League debut with Miami in 2025, posting a 4-2 record and 7.34 ERA (25 ER/30.2 IP) in 31 relief appearances with 34 hits (five home runs), 22 walks, and 36 strikeouts. The 6-foot-2 left-hander also made 29 appearances with Triple-A Jacksonville, going 3-1 with a 3.41 ERA (13 ER/34.1 IP) in his sixth season with the organization (2019-25). A native of Stafford, Conn., Simpson was originally selected by Miami in the 32nd round (951st overall) of the 2019 First-Year Player Draft out of Columbia University (New York, N.Y.).
The Miami Marlins’ 2026 regular season begins with Opening Day under the lights on Friday, March 27, against the Colorado Rockies at 7:10 p.m. Tickets are available at Marlins.com/tickets.
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