Montero is scheduled to start Sunday's game against the Phillies, Matt Ehalt of The Record reports.
With Zack Wheeler (biceps) expected to return to the starting rotation for Saturday's game, Montero will simply have his next start pushed back a day to fill in for the recently injured Robert Gsellman (hamstring). Montero has already made three spot starts for the Mets this season, and while he struggled in his first two outings, he struck out seven and allowed just one run in 5.2 innings of work against the Giants in his most recent start. He could be a decent streaming option against a Phillies squad that has scored the second fewest runs in the majors this season.