Corey Oswalt was optioned to the Mets' Alternate Site following Sunday night's game.
The move came after Oswalt allowed five earned runs on seven hits, three of them home runs, in four innings against the Braves.
Oswalt appeared in just two big league games in 2019 where he allowed nine earned runs in 6.2 innings (12.15 ERA).
A corresponding move will be made on Monday morning before the Mets take on the Boston Red Sox.