Since Aaron Loup departed the Mets for the Angels, New York has been without a major league left-handed reliever on their 40-man roster.

Until now.

The Mets announced on Sunday they acquired LHP Joely Rodríguez from the Yankees in exchange for RHP Miguel Castro, dealing from their stock of right-handed relievers in an effort build competence on the left side of their bullpen.

This is the first time the Mets and Yankees have made a trade exchanging major leaguers since 2004.

Rodriguez, 30, had a 4.66 ERA in 52 appearances between the Rangers and Yankees in 2021, but pitched to a 2.84 ERA in 21 appearances after being dealt to the Bronx, allowing 21 hits and six walks with 17 strikeouts in 19 innings following the trade. Overall, lefties have hit .272 with a .718 OPS against Rodríguez throughout his career. While that might seem uninspiring, his marks were vastly better in 2021 when left-handed hitters hit .203 with a .558 OPS against him. The Mets will also likely try to use him as a LOOGY as best they can with the three-batter minimum, as righties have hit .291/.352/.427/.779 against him in his career. Rodríguez does not have any minor league options remaining, per FanGraphs, and while his service time might suggest he is under control through 2025, his contract stipulates he can become a free agent after the 2022 season, according to Joel Sherman of the New York Post.

The left-hander’s strongest asset is his change-up which had a -6 run value in 2021 and helps put him in the 97th percentile in chase rate, per MLB Statcast.

Castro, 27, was under team control through the 2022 season. He appeared in 69 games for the Mets in 2021 and had a 3.45 ERA with 43 walks and 77 strikeouts over 70 1/3 innings pitched. His command eroded after the first three months of last season, pitching to a 4.17 ERA while allowing 21 walks in only 36 2/3 innings down the stretch. New York will also shed $620,000 in payroll following the deal.

Certainly, exchanging a higher upside, swing-and-miss arm in Castro for a pitcher who depends more on weak contact against left-handers seem as though the bullpen is weaker now than it was before. But again, the Mets were arguably overstocked on the right side of the bullpen and very much needed a major league left-handed reliever to help neutralize the elite left-handed threats in the National League East such as Bryce Harper, Juan Soto, Matt Olson and Kyle Schwarber. And Castro’s inconsistent command certainly made him the most expendable piece in the bullpen to address this glaring need.

With the expanded rosters over the first month of the season, the Mets will easily be able to carry Rodriguez and perhaps Chasen Shreve or Álex Claudio at the jump.