The Mets optioned Hagenman to Triple-A Syracuse on Monday.
Hagenman had spent all season on the injured list while recovering from a fractured rib before he was activated last Wednesday. The 29-year-old righty made two appearances (one start) during his abbreviated stay with the Mets, giving up two runs on three hits and one walk while striking out two batters across four innings. He'll give up his spot on the 28-man active roster to right-hander Jonah Tong, who was recalled from Triple-A ahead of his start Monday in Miami.