McGowan was recalled from Triple-A Las Vegas on Tuesday, Matt Ehalt of The Record reports.
The 25-year-old has made just one major-league appearance, conceding one run in 1.1 innings of work. McGowan compiled an unimpressive 4.85 ERA and 57:25 K:BB through 65 innings with Las Vegas, so he'll likely serve in a low-leverage bullpen role for the Mets down the stretch.