PITTSBURGH -- Steelers safety Troy Polamalu sprained the medial collateral ligament in his left knee late in the first half of his team's 13-10 season-opening overtime victory over the Tennessee Titans on Thursday night.

Steelers coach Mike Tomlin said the injury usually sidelines a player from 3 to 6 weeks.

"They are reading the scans and so forth," Tomlin said. "It is speculation (how long Polamalu will be out) at this point."

Polamalu was injured when Titans tight end Alge Crumpler fell on him as Steelers defensive end Aaron Smith blocked Rob Bironas' 31-yard field-goal attempt with about three minutes left in the half. Polamalu was attempting to pick up the ball.

Before he was hurt, Polamalu made a one-handed interception and led both teams in tackles with six.

Tomlin said there is a chance that Polamalu's injury could be deemed worse once further tests are run.

"I'm sure there's a possibility of it, but I don't have any concrete evidence that there is anything more than that," Tomlin said.

A two-time All-Pro safety, Polamalu also has been chosen for the past five Pro Bowls. He's considered one of the NFL's premier defensive players.

"We definitely were aware of him not being in there," said Titans quarterback Kerry Collins, who led a touchdown drive immediately after Polamalu was injured. "You calls the plays based on coverage, and sure, we'd like to say, 'Hey, he's out of the game,' and do a couple of different things."

Though Polamalu potentially could be sidelined for much of the first half of the season, the injury could have been much worse. An anterior cruciate ligament injury might have put Polamalu out the rest of the season.

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Rod Woodson, the Hall of Fame cornerback, tore up his knee during the Steelers' 1995 season opener, needed major surgery and didn't return until the Super Bowl. He was the first player to return from such an injury and play in the same season.

Steelers players are off until Monday, when the team is scheduled to practice again.

Copyright 2009 by The Associated Press

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