Castano is listed as the Marlins' starter for the second game of Friday's doubleheader against the Nationals, but manager Don Mattingly indicated he could pitch in relief in the afternoon game, Jordan McPherson of the Miami Herald reports.
Castano should feature at some point in one of Friday's games, though exactly when remains to be seen. If Castano is used in Game 1, expect Robert Dugger to get the call to start Game 2.