Falter was recalled Friday ahead of his scheduled start against the Mets.
Falter has made one start and four relief appearances at the big-league level this season, allowing five runs on 13 hits in 12 innings of work while striking out seven batters and walking just two. He's recently been stretching out for a starting role with Triple-A Lehigh Valley, where he's thrown 10.1 scoreless innings while striking out half the batters he's faced. Jose Alvarado was optioned to clear space on the roster.