It might have something to do with his inability to run the correct pass routes, coach Mike Nolan intimated.

Davis has exceptional straight-ahead speed and strength. He has been spending time after practices working with quarterback J.T. O'Sullivan on down-the-field pass routes. Davis is not known as an accomplished route-runner.

"A lot of it has to do with J.T.'s trust that he has to be where he has to be on the route, and some of it is just Vernon's understanding of where he has to be, as well," Nolan said. "So extra work is always helpful for any player. Vernon is not short on work ethic."

Nolan stated that Davis is also not short on emotion. Davis was benched late in the 49ers' loss to the New Orleans Saints two weeks ago after his emotions spewed to the surface after catching a pass late in the fourth quarter.

"He has to control that," Nolan said. "It is a team sport and whether it's Vernon or anyone, they have to recognize for us to win, you've got to put the team in front of yourself."

--The 49ers are 12-2 when running back Frank Gore has 20 or more rushing attempts. Gore leads the NFL with 603 yards from scrimmage. Since the start of 2006, he ranks second in the league with 4,321 yards.

--Safety Michael Lewis plays against his former team for the first time. Although he might not have left the Eagles on good terms, he said he is still grateful that the organization drafted him.

A routine physical while in college revealed Lewis was living with a heart defect that had gone undetected until that point. He was diagnosed with atrial fibrillation, a disorder found in about 2.2 million Americans in which the heart's two small upper chambers, the atria, quiver instead of beat effectively.

"At first, not knowing about the situation, it kind of scared me," Lewis said. "Then, I figured out what it was and how I could manage it."

Lewis has managed it throughout a standout at Colorado. He has made it to a Pro Bowl with the Eagles. Last season, he ranked second on the San Francisco 49ers with 139 tackles.

"At that time with a heart condition, teams were backing off guys," Lewis said. "They did their research and thought I was fit enough to play for them."

--The 49ers twice passed on former California receiver DeSean Jackson in the draft. The organization selected defensive lineman Kentwan Balmer in the first round. Prior to their pick in the second round, the 49ers considered a wide receiver, but he wasn't Jackson. The names of Texas receiver Limas Sweed and USC offensive lineman Chilo Rachal were written on two cards. A brief discussion ensued before Rachal was named as the pick.

"At the time we had a couple other players we felt we - not necessarily needed - but we thought would help us more quickly," Nolan said. "We thought he'd (Jackson) fit a specific role, as far as where he'd line up in the slot and all that. That is an important role. We at no time diminished his importance just because of his size, because he is an explosive player."

BY THE NUMBERS: 13.3 - Average yards per reception for the 49ers this season, a significant improvement over last season when the 49ers averaged 9.8 yards per catch. The 49ers rank second in the league this season after ranking 31st a year ago.

QUOTE TO NOTE: "I apologize for being a little bit late. Obviously, meetings run a little bit longer when you've got things to fix" - 49ers coach Mike Nolan on appearing about 20 minutes later than usual for his Monday press conference.