That deal looks unlikely to be made permanent unless the 24-year-old breaks into Hughes' first-team and impresses over the remainder of his stay.
La Liga club Real Betis showed some interest but the move to the Seville outfit never came off, leaving Castillo in the same boat as Felipe Caicedo.
"They have both come back to the club," confirmed Hughes.
"There were deals on the table we thought were going to be concluded but in the end they weren't.
"It is disappointing for both of them. We thought they were good opportunities but in the end it wasn't to be."




