Steelers offensive guard David DeCastro suffered a major knee injury during Saturday night's preseason game against the Buffalo Bills.
DeCastro, the team's first-round pick out of Stanford in last April's draft, tore his MCL and dislocated his knee cap. There are some reports that say he also tore his ACL, but the Steelers have yet to release official information.
DeCastro is most-likely out for the season, and there is no timetable for his return.
The Steelers wrap up the preseason schedule Thursday against Carolina at Heinz Field.
The season-opener is Sunday, September 9, against Peyton Manning and the Denver Broncos at Sports Authority Field at 8:20 p.m. EDT.