Hart was called up from Triple-A Syracuse by the Mets on Sunday.
Hart was claimed off waivers Saturday after being designated for assignment by the Brewers and didn't have to wait long before making his way to the majors. The 28-year-old spent the bulk of the season at Triple-A where he posted a 4.10 ERA, 1.50 WHIP and 30:13 K:BB over 37.1 innings, but he also had 6.2 scoreless frames in the big leagues.