According to CBS NFL insider Jason La Canfora, the team has checked in with former Eagles defensive coordinator and offensive line coach Juan Castillo.
Former Eagles OL coach/DC Juan Castillo interviewing with the Cardinals. Would imagine its for the OL spot vacated by Russ Grimm— Jason La Canfora (@JasonLaCanfora) January 9, 2013
Castillo was the Eagles' offensive line coach from 1998-2010, when he was moved into the defensive coordinator position. He was fired from that post in October 2012, though.
La Canfora notes the Cardinals' interest would likely be for his work with offensive linemen, as that is an area the team has struggled with for the better part of forever.
However, that they would be looking to add to the coaching staff without having a coach on board yet would seem like a questionable move.