Plassmeyer is with the Phillies on Saturday and is expected to start the nightcap of the doubleheader against the Mets, Matt Gelb of The Athletic reports.
The Phillies have to cover 27 innings this weekend and are locked into the fourth seed in the National League even if they lose all three contests, so their primary concern will likely be ensuring that their most important arms stay fresh for the postseason. That could mean a first major-league start for Plassmeyer, a 26-year-old who's MLB experience to date consists of 7.1 innings of relief work last season. He owns a 5.05 ERA and 1.46 WHIP in 14 starts and two relief appearances for Triple-A Lehigh Valley this season.