Sewald was recalled from Triple-A Las Vegas on Monday, Marc Carig of Newsday reports.
Sewald was called up to take the roster spot of Noah Syndergaard (back), who recently landed on the disabled list with a partial tear in his lat muscle. The 26-year-old will slot into the Mets' bullpen, though he likely won't be used in any high-leverage situations. This will be Sewald's second major-league stint this season; he allowed two runs across 1.1 innings in his last cup of coffee. This is expected to be another short stay in the majors for Sewald, as the Mets are expected to recall Rafael Montero from Las Vegas to take Syndergaard's next turn in the rotation Friday.