Ryan Joseph Zeferjahn (born February 28, 1998) is an American professional baseball pitcher for the Los Angeles Angels of Major League Baseball (MLB).
A native of Topeka, Kansas, Zeferjahn played college baseball at the University of Kansas. In 2017, he played collegiate summer baseball with the Falmouth Commodores of the Cape Cod Baseball League.
Zeferjahn was drafted by the Boston Red Sox in the third round, with the 107th overall selection, of the 2019 Major League Baseball draft. He made his professional debut with the LowâÂÂA Lowell Spinners, logging a 4.50 ERA in 12 starts. Zeferjahn did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.
Zeferjahn returned to action in 2021 with the rookieâÂÂlevel Florida Complex League Red Sox and SingleâÂÂA Salem Red Sox. In 16 starts between the two affiliates, he compiled a 1âÂÂ4 record and 5.98 ERA with 59 strikeouts across innings pitched. Zeferjahn split the 2022 campaign between the HighâÂÂA Greenville Drive and DoubleâÂÂA Portland Sea Dogs. In 34 appearances pitching mainly in relief, he accumulated a 5âÂÂ4 record and 5.05 ERA with 80 strikeouts over innings pitched.
Zeferjahn spent 2023 with Portland, also making two scoreless outings for Salem. In 34 appearances out of the bullpen for Portland, he recorded a 5.02 ERA with 68 strikeouts across 43 innings of work. Zeferjahn began the 2024 season with Portland, and was promoted to the TripleâÂÂA Worcester Red Sox after seven scoreless appearances. In 18 games for Worcester, he registered a 5.47 ERA with 31 strikeouts and 4 saves over innings.
On July 30, 2024, Zeferjahn, Matthew Lugo, Yeferson Vargas, and Niko Kavadas were traded to the Los Angeles Angels in exchange for Luis GarcÃÂa. In 5 games for the TripleâÂÂA Salt Lake Bees, he posted a 2.35 ERA with 8 strikeouts. On August 23, Zeferjahn was selected to the 40-man roster and promoted to the major leagues for the first time. In 12 appearances for Los Angeles during his rookie campaign, Zeferjahn recorded a 2.12 ERA with 18 strikeouts over 17 innings of work.
On April 6, 2025, Zeferjahn recorded his first career win after tossing a scoreless sixth inning against the Cleveland Guardians.