The Phillies outrighted Castillo to Triple-A Lehigh Valley on Sunday after he cleared waivers.
Castillo no longer possesses a spot on the Phillies' 40-man roster, but he'll remain in the organization as pitching depth at the Triple-A level. Between stops with Lehigh Valley and Double-A Reading this season, Castillo has posted a 7.62 ERA over 52 innings.