Steelers first-round pick David DeCastro has a torn MCL, but the team is unsure if he also tore his ACL.

The right guard is scheduled to undergo an MRI on Sunday afternoon to determine the severity of the injury.

If he tore both ligaments, he'll likely miss the entire 2012 season. Just an MCL injury would cost him about half the year.

Pittsburgh quarterback Ben Roethlisberger blamed the injury on artificial turf.