The Padres pulled Castillo off his rehab assignment at Triple-A El Paso after he experienced renewed discomfort in his left forearm during his appearance Saturday, Kevin Acee of The San Diego Union-Tribune reports.
Castillo was evaluated by team doctors in San Diego on Monday, but it's unclear what the medical staff concluded after its examination. In any event, Castillo's shutdown will push back any potential activation from the 60-day injured list, which was initially expected to come later this week.