SAN FRANCISCO -- The San Francisco 49ers shook up their special teams Tuesday, releasing kicker Jose Cortez and punter Jason Baker.

Cortez has struggled in his second season as the club's kicker, making 18-of-24 field goals.

Two weeks ago, Cortez missed a 41-yard field goal in overtime in a 20-17 loss at San Diego. The former XFL product also missed a 27-yard field goal on the final play of regulation in a 23-20 overtime victory at Oakland on Nov. 3.

Coach Steve Mariucci replaced Cortez as the club's kicker in Monday night's 38-17 loss to Philadelphia, giving the job to fourth-round pick Jeff Chandler.

Baker also has been struggling, as his net average of 32.0 yards was the lowest in the league. He had a punt returned 76 yards for a touchdown in Monday's game.

Mariucci also said Tuesday that running back Kevan Barlow, who suffered a sprained right knee against the Eagles, would undergo arthroscopic surgery for the injury sometime this week. He is expected to miss at least this week's game vs. Seattle.

Barlow shares time in the backfield with Garrison Hearst and is second on the team with 514 rushing yards and four touchdowns.

San Francisco, which has lost consecutive games for the first time since the 2000 season, holds a two-game lead atop the NFC West.