The Mets recalled Warren from Triple-A Syracuse on Tuesday.
With Joey Gerber (finger) headed to the injured list, Warren will join the big-league roster to fill the open spot in New York's bullpen. The 30-year-old righty allowed just one earned run over 9.1 innings with the Mets last season but finished with a 5.16 ERA and 1.42 WHIP over 52.1 frames in Triple-A. He's off to a much better start this year (1.23 ERA through 7.1 IP) but will still likely be limited to middle relief while in the majors.