Megill had his contract selected by the Mets and is starting Wednesday's game versus Atlanta, Anthony DiComo of MLB.com reports.
The right-hander was previously announced as the starter for Wednesday's series finale, and now he's officially joined the major-league roster ahead of his debut. Megill has a 3.35 ERA, 1.09 WHIP and 59:12 K:BB over 40.1 innings between Double-A Binghamton and Triple-A Syracuse this season.