The left guard was injured in the 1st quarter against the Buffalo Bills on Saturday night and had to be taken off the field on a cart. On the play, DeCastro was defending against Marcell Dareus when he fell awkwardly and landed on top of his right leg.
If the Stanford product is out for an extended period of time, it could be a major blow to a Steelers offensive line that hasn't been solid in recent years.
The offense is already undergoing a lot of changes with first-year offensive coordinator Todd Haley's new scheme and Rashard Mendenhall recovering from a torn ACL. The loss of DeCastro would just compound those issues.