The Mets officially selected Peterson's contract from their alternate training site Tuesday in advance of his scheduled start against the Red Sox.
New York designated Ty Bashlor for assignment to clear spots on the 40-man roster and 30-man active roster for the 24-year-old southpaw. Peterson whiffed 24.5 percent of the batters he faced at the Double-A level in 2019 and excelled at generating groundballs, but the latter attribute could contribute to an inflated WHIP in the majors, especially with a shaky Mets defense behind him.