Falter will start Sunday's game against the Marlins, Matt Gelb of The Athletic reports.
Falter has made 12 appearances out of the bullpen for Philadelphia since being activated from the COVID-19 injured list in mid-August, and he'll now receive his first MLB start in the season finale. The left-hander made six starts at Triple-A Lehigh Valley this season, but he hasn't covered more than three frames in an outing since mid-June. Falter may pitch as long as he can Sunday, though he's unlikely to have the workload of a traditional starter given his lack of buildup.