Manager Don Mattingly said Richards will remain in the Marlins' rotation, Joe Frisaro of MLB.com reports.
Richards allowed five runs across 4.1 innings in his major-league debut against the Red Sox on Monday, but he apparently impressed Mattingly enough to stick in the Marlins' thin rotation for the time being. The 24-year-old hadn't pitched above Double-A prior to Monday's outing, though he posted a solid 2.87 ERA and 77 strikeouts across 75.1 innings with Double-A Jacksonville in 2017. It's best to wait and see if he settles in against major-league hitters before considering him for fantasy purposes.