PHILADELPHIA -- Eagles Pro Bowl cornerback Troy Vincent left practice Thursday with a knee injury, leaving his status for Sunday's opener against St. Louis uncertain.

	Vincent

Vincent got hurt during a non-contact drill when he banged knees with linebacker Mike Caldwell. Vincent was helped off the field, but was able to put pressure on his knee. He was taken for an MRI exam, and the extent of the injury wasn't immediately known.

"Troy has a hyperextended knee," coach Andy Reid after practice. "We'll know more later."

If Vincent can't play against the Rams, Al Harris would join Bobby Taylor as the other starter at cornerback.

Even if Vincent plays, Philadelphia's secondary has all it can handle against St. Louis' high-powered offense. The Rams scored 540 points last year, third most in league history, and a 14-point improvement over the prolific output of their Super Bowl season in 1999.

Quarterback Kurt Warner threw for 21 touchdowns in 11 games; Isaac Bruce caught 87 passes for 1,471 yards; and running back Marshall Faulk scored a league-record 26 TDs, becoming only the second player to top 2,000 yards rushing and receiving three straight years.

"It's a tremendous challenge for us," free safety Brian Dawkins said. "We feel we're one of the best secondaries in the league, if not the best. They have the best receiving corps, and you have to include Marshall in that. We know they're going to make plays, but we've got to limit yardage after the catch and not let them get any long plays."

Rams coach Mike Martz is impressed by Vincent, Taylor, Dawkins and the rest of the group.

"I think it is a great challenge for our receivers," he said. "I think overall that this is the best secondary I have seen since I have been here. This is a playoff atmosphere for this game. You don't get too many of these during the season."