49ers' Smith expected to miss 3-4 weeks with shoulder injury

San Francisco 49ers quarterback Alex Smith, who separated his shoulder in Sunday's 23-3 loss to Seattle, is expected to miss the next three to four weeks, the NFL Network's Adam Schefter reported.

Coach Mike Nolan said the 49ers won't set a target return date for Smith until Thursday, after the swelling has subsided in his shoulder. Nolan did say the injury won't require surgery.

Though similar injuries sometimes require two to three months of recovery, Nolan expressed hope Smith might return by Oct. 21, when the 49ers visit the New York Giants in their first game after a bye week.

Smith suffered a third degree shoulder separation after being driven hard to the ground on a sack by Seattle's 308-pound defensive tackle Rocky Bernard on San Francisco's first drive.

Trent Dilfer, who replaced Smith and went 12-of-23 for 123 yards and two interceptions against the Seahawks, will get the start for the 49ers this Sunday against Baltimore, making it the second straight week he will play against one of his former teams.

Nolan also announced on Monday that tight end Vernon Davis, recovering from a sprained MCL in his right knee, will not play against the Ravens, either.

Copyright 2007 by The Associated Press