Arano didn't pitch in Tuesday's doubleheader against the Nationals due to right elbow soreness, Matt Breen of The Philadelphia Inquirer reports.
Arano last took the mound Sunday against the Mets, and also pitched in Saturday's game. The severity of the issue remains unclear at this point, and the 23-year-old should be considered day-to-day for the time being. Arano has a 2.50 ERA, 1.19 WHIP and 56:15 K:BB over 54 innings this season.