"Brian Westbrook has no illusions of grandeur about his new gig in San Francisco.

The longtime Philadelphia Eagles running back said Monday that he knows that Frank Gore is, in his words, "the man," in the 49ers' offense and that he is happy to play behind him.

But that doesn't mean that Westbrook is incapable of becoming a No. 1 running back again if called upon. "From my workouts I've had this offseason, from my conditioning this offseason, I don't see why I can't come in and carry the load," he said in his first news conference.

The 49ers elbowed ahead of several other suitors Monday to sign Westbrook, 30, to a one-year deal that's worth as much as $2.5 million. The signing was first reported by The Bee.

Westbrook's initial role will be as Gore's top backup, a job that until Friday belonged to second-year player Glen Coffee. On Friday, Coffee unexpectedly told the 49ers he was leaving football to return to the University of Alabama. Coffee's retirement papers were filed Monday, and Westbrook will take over Coffee's roster spot.

Coach Mike Singletary said the 49ers haven't yet discussed whether Westbrook's presence will mean fewer carries for Gore, who has taken the lion's share of the snaps for the 49ers since 2006 but who has missed games in each of the last three seasons with ankle injuries.

"When I talked to Frank, I told Frank that it's something where we'll see how it goes," Singletary said of reducing Gore's carries. "Frank is a guy who wants the ball, and I understand that. It is one of those things where I want him to understand that we want him as long as we can have him."

Singletary also said that while coaches were impressed with rookie Anthony Dixon's 100-yard performance in Sunday's win in Indianapolis, Dixon has plenty to learn."