Rice left Sunday's game against the Cleveland Browns with just under 10 minutes left after catching a short pass for a 4-yard gain. An MRI on Monday revealed "a significant contusion," according to Ravens coach John Harbaugh.
Asked if he expected Rice to play against Pittsburgh, Harbaugh said, "We'll see how he fares throughout the week. We'll see how it heals."
The team wouldn't reveal whether Rice hurt his left or right knee.
Rice was one of two NFL running backs (with Tennessee's Chris Johnson) to exceed 2,000 yards from scrimmage in 2009. He leads the Ravens this season with 210 rushing yards, including 80 on 15 carries in Baltimore's 24-17 victory over Cleveland.
If Rice can't play against Pittsburgh, Willis McGahee will start, fullback Le'Ron McClain will probably be given more carries and third-stringer Jalen Parmele could be pressed into action.
"Willis has obviously proven himself; Le'Ron is going to be able to run the ball," Harbaugh said. "Jalen Parmele is a guy you all haven't seen too much, but if he gets a chance to run the ball, he can do it, too. We like our running back situation."
But Rice excelled against the Steelers last season and would be sorely missed Sunday if his injury doesn't sufficiently heal. He ran for 88 yards and had five catches for 67 yards in a 20-17 overtime win at Baltimore, then rushed for 141 yards in a 23-20 loss at Pittsburgh.
"Ray Rice is a good player," Harbaugh said. "We'd sure rather have him."
This is an important game for the Ravens, who hoped to take control in the AFC North after the Cincinnati Bengals lost their opener against the New England Patriots and the Steelers were forced to play their first four games without suspended quarterback Ben Roethlisberger.
But Baltimore (2-1) lost at Cincinnati, and Pittsburgh is off to a 3-0 start. With a win Sunday, the Ravens would be no worse than tied atop the division after already playing on the road against the Bengals and the Steelers.
"It's a great opportunity for us," Harbaugh said.
Having Rice would help. The third-year pro hurt his knee upon being tackled by Ahtyba Rubin, and although Rice was eager to get back in during the closing minutes of a tight game, he couldn't operate at peak efficiency.
"It's a pretty significant bruise, and he just didn't feel like he could go," Harbaugh said.
After the game, however, Rice said, "Right now everything is standard. ... Everything looks positive right now."
McGahee is averaging just 2.3 yards per carry this season, but he's a veteran back and has Baltimore's lone rushing touchdown this season. After Rice left, McGahee ran six times for 25 yards, and McClain gained 4 yards on his only carry.
"Willis is 240 pounds, and he brings it. He's a load," Harbaugh said. "I like the way Willis runs and I like his personality. I like the way he's practiced and the way he's prepared for this season. He'll be ready to go."
Ravens defensive lineman Cory Redding will be examined this week to determine if he can return from the concussion he sustained during the third quarter against the Browns. Harbaugh also said there was nothing new to report on right tackle Jared Gaither, who has yet to play this season because of a back injury.
Copyright 2010 by The Associated Press