The Boston Red Sox selected Fernandez in the 23rd round, with the 700th overall pick, in the 2018 Major League Baseball draft.[2] Fernandez spent five minor-league seasons in the Red Sox organization, reaching Double-A in 2022 and Triple-A in 2023.[3] In 26 Triple-A games with the Worcester Red Sox, all in relief, Fernandez posted a 3–3 record with a 6.16 ERA while striking out 35 batters in 30+2⁄3 innings.[3][4]
St. Louis Cardinals
On December 6, 2023, the St. Louis Cardinals selected Fernandez from the Red Sox in the Rule 5 draft.[5][6] He made the Cardinals' Opening Day roster as part of the team's bullpen.[7] He made his debut on April 3, 2024, in a game against the San Diego Padres. Fernandez pitched the entirety of the 8th inning, allowing a hit and a walk and striking out three batters.[8]