Peter Diana, Post-Gazette Ravens linebacker Bart Scott sacks Ben Roethlisberger in the second quarter. The Steelers quarterback was shaken up on the play, but returned to finish the game. Click photo for larger image.

BALTIMORE -- The Baltimore Ravens shut out the Steelers 27-0 today, dropping the defending Super Bowl champions record to 4-7. Baltimore leads the AFC North Division at 9-2.

The Ravens racked up a team-record nine sacks and were plus-three in turnovers as they stuffed the Steelers. Linebacker Bart Scott stepped in front of Cedrick Wilson to pick off a Roethlisberger pass with about two minutes remaining to seal the shutout.

In his postgame press conference, head coach Bill Cowher revealed that All Pro safety Troy Polamalu has a "significant" knee injury.

In a somber exchange with reporters, Cowher said the Steelers had "A very pitiful performance out there today."

"Where we go from here is we've got to line up and play this thing out. It starts next week," Cowher said.

Matt Stover kicked his second field goal of the game, from 40 yards with 4:15 left in the game to make it 27-0.

Baltimore scored its third touchdown when cornerback Corey Ivy hit Roethlisberger as he was about to throw, knocking the ball out of his hand on a third-down play that began at the Raven's 30.

Linebacker Adalius Thomas picked up the loose ball and ran down the sideline 57 yards for the touchdown that made it 24-0.

The Ravens led the Steelers 17-0 at halftime, after a quarter in which quarterback Ben Roethlisberger left briefly with an injury.

Roethlisberger was hurt with 3:27 left in the second quarter when he was sacked by linebacker Bart Scott. The quarterback jogged off the field and sat on the bench as doctors talked to him. Charlie Batch replaced him for one play. Roethlisberger had a chest injury and returned for the final play of the half.

Jamal Lewis scored on a 1-yard run with 4:21 left in the first half for Baltimore's second touchdown and a 14-0 lead. It capped a 47-yard drive on eight plays.

Matt Stover kicked a 37-yard field goal with eight seconds left in the half.

The Ravens opened a 7-0 lead on the Steelers in the day's first quarter.

Baltimore quarterback Steve McNair made it look easy on his first drive. He completed all four passes he tried for 51 yards, the last one of 20 yards and a touchdown to tight end Todd Heap, who put a move on cornerback Deshea Townsend and was wide open in the right back corner of the end zone.

More details in tomorrow's Pittsburgh Post-Gazette.