Megill will have his contract selected by the Mets and start Wednesday's game against Atlanta, Justin Toscano of The Bergen Record reports.
The 25-year-old has a 3.77 ERA, 1.13 WHIP and 17:5 K:BB over 14.1 innings (three starts) at Triple-A Syracuse, and he'll be promoted to make his big-league debut Wednesday. It'll likely be a spot start for Megill, though the status of Marcus Stroman (hip), who exited Tuesday's game with an injury, could open a spot in the rotation.