Falter was recalled from Triple-A Lehigh Valley as the 27th man to start the second game of Friday's doubleheader against the Nationals.
Falter has been working as a starter in Lehigh Valley this season, and he posted a 2.77 ERA and 0.92 WHIP in 13 innings over two starts after being demoted in late May. However, he'll rejoin the major-league club to make a spot start during Friday's nightcap.