ST. LOUIS, MO. -- Willie Parker, the NFL's leading rusher, had a fractured right fibula and is done for the season.

Parker's injury occurred on his first carry of the game and there were unconfirmed reports that his foot got caught in the artificial turf at the Edward Jones Dome.

The fibula runs from the knee to the ankle and is the smaller of the two bones in the lower leg.

The Pro Bowl halfback gained one yard after taking a pitch from Ben Roethlisberger and running around to the right.

After Parker was tackled, he took himself out of the game and was carted off the field into the Steelers locker room.

Najeh Davenport replaced Parker as one of only two healthy backs left on the gameday active roster. Fullback Carey Davis was the only other back in uniform because they made rookie halfback Gary Russell inactive for the game. The Steelers have only four backs on their roster after fullback Dan Kreider was placed on injured reserve.

Davenport ran 12 times for 65 in the first half.