DENVER — The league is investigating whether Denver Broncos coach Mike Shanahan broke a rule when he lied about quarterback Jake Plummer's injury in a victory at San Diego.

The Broncos initially said Plummer suffered a concussion in the second quarter of Sunday's 37-13 win over the Chargers. After the game, Shanahan announced his quarterback had a separated right shoulder.

He said he lied because the Chargers would have had an advantage if backup Steve Beuerlein got hurt and Plummer had to re-enter the game. Denver carries two quarterbacks.

NFL spokesman Greg Aiello said the league expects injury information to be as accurate as possible.

Rules for reporting in-game injuries aren't as specific as pregame injuries, which require a designation — out, doubtful, questionable and probable.

Shanahan could be fined if the league determines a rule was broken.

"To share with somebody that Jake has a separated shoulder and could not throw and our quarterback goes down, we have a good chance to lose the football game," he said.

Plummer and Denver running back Clinton Portis are each expected to practice this week after missing the second half of the game.

Notes

• Atlanta quarterback Michael Vick, who broke a bone in his right leg during an Aug. 16 exhibition game, has a target date of Oct. 13 at St. Louis for his 2003 regular-season debut.

But Falcons coach Dan Reeves said it's more realistic Vick would return a week later for a home game against New Orleans.

• Tests showed Tennessee right guard Benji Olson, a former Washington Husky, didn't tear a ligament in his right knee when he was hurt Sunday. His status for this weekend's game against New Orleans is uncertain.