Frank Gore is frustrated. And the Pro Bowl running back says it's time to take it out on the Seahawks. The reigning NFC rushing champion has mostly been contained during San Francisco's first three games as the team's struggling offense has sunk to the bottom of the NFL rankings. The 49ers have still managed a 2-1 record to take into Sunday's battle with Seattle for first place in the NFC West, but Gore is upset that he and the offense aren't doing their part.

The 49ers changed punt returners on Tuesday, cutting Brandon Williams and signing Michael Lewis, the former beer truck driver who rose to fame with the Saints. Williams, the 49ers' third-round pick in 2006, never was particularly impressive as the 49ers' designated punt returner, and the former Wisconsin star couldn't crack San Francisco's rotation of receivers.

One day later, tight end Vernon Davis' much-debated near-catch in the third quarter Sunday still shadowed the 49ers - and not only because they disagreed with the referee's ruling. Davis sprained the medial collateral ligament in his right knee on the play, an MRI exam revealed Monday. He probably will miss the next two games, the team announced, removing a key option from an offense already struggling to reach the end zone. Davis caught four passes for 56 yards in Sunday's 37-16 loss to Pittsburgh, in the first game after he requested a more prominent role in the offense. Now, as the 49ers prepare for home games against Seattle and Baltimore the next two weeks, Davis' injury temporarily leaves him with no role in the offense. Backups Delanie Walker (the better receiver) and Billy Bajema (more of a blocker) figure to share tight-end duties in Davis' absence.

49ers tight end Vernon Davis suffered a sprained right knee in Sunday's 37-16 loss to the Steelers. 49ers coach Mike Nolan confirmed the injury after the game and said Davis will undergo an MRI exam on Monday.

Linebacker Manny Lawson will miss the rest of the 49ers' season after tearing a ligament in his left knee. Lawson, a starting outside linebacker in the 49ers' 3-4 defensive scheme, went down with the injury during Wednesday's practice. The injury didn't initially appear to be serious, and Lawson rode on a stationary bike for the rest of the team's workout. But tests determined Thursday that Lawson tore his anterior cruciate ligament.

Alex Smith and his 49ers looked awful on Bill Walsh Field until the very last minute. Arnaz Battle scored on a 1-yard end-around with 22 seconds to play, and the 49ers emerged from an awful offensive night with an 86-yard scoring drive to cap a 20-17 victory over the Cardinals in the NFL's final opener Monday night.

Frank Gore missed a month with a broken right hand, but the 49ers running back insists he won't be thinking about the injury Monday night. Gore said he has not yet decided whether he will play with the padded glove he has at times worn in practice this week. One of the worries is that it will affect his grip on the ball, a problem Gore has had in each of the past two seasons. San Francisco coach Mike Nolan said Thursday he expected the hand injury might prompt the Cardinals to put a little more emphasis on stripping the ball Monday night. "They'll wrap him up, and the other guys will come in and probably tug away at the ball," he said. "That's what backs have to expect -- this week's not different than any other week."

The 49ers signed defensive end Atiyyah Ellison on Wednesday. Terms of the deal were not disclosed. The 6-3, 318-pound Ellison, who was a third-round pick of the Panthers in 2005, never has played in a regular season game. He spent the majority of last season on the practice squad of the Ravens.

Running back Frank Gore, held out of all four preseason games while his broken right hand healed, will bring fresh legs to the 49ers' regular-season opener Monday night against Arizona. For players, especially those who carry or catch the ball, "fresh legs" ranks just behind "day off" on the scale of importance. Gore looked particularly quick on the few handoffs he took in Monday's practice without pads. It's a reflection of him working hard on his conditioning while he was out and of not taking a beating for the last month in camp. "I feel good," he said. "Coaches were working me out, keeping me in shape with explosive drills."