"The twists and turns continued at 49ers training camp Monday, with longtime Philadelphia Eagles running back Brian Westbrook signing a one-year deal hours after defensive lineman Kentwan Balmer was traded to Seattle.

Westbrook, a two-time Pro Bowl selection in eight seasons in Philadelphia, adds depth in the backfield after the retirement of Glen Coffee last week. Westbrook is the Eagles' all-time leader in yards from scrimmage (9,785), but he missed eight games last season because of two concussions and an ankle injury.

Balmer was dealt to the Seahawks for a 2011 sixth-round draft pick. Balmer, a first-round selection in 2008, never started for the 49ers and didn't return to training camp after leaving the team Aug. 9. As of Wednesday, his absence had been unexcused.

"When he wasn't here that morning, I was done," coach Mike Singletary said. "I was already on up the road.

"I think he's a fine young man, but obviously there are some things he needs to deal with."

Westbrook was released by the Eagles in February, but during an introductory news conference at 49ers headquarters, the 30-year-old said he is "fully healthy" and not worried about the concussion issue after doing "a lot of homework."

"Every doctor I talked to has basically said you're at risk, just like anybody playing football who has never sustained a concussion," Westbrook said. "I can go out there worry-free."

Westbrook said he was not familiar with the 49ers' system but chose San Francisco over several other suitors because he respects Singletary and wanted to go to a team that "can win right now."

"My No. 1 concern throughout this process was going to a winning team," said Westbrook, who also visited with Washington, Denver and St. Louis during the summer. "I think I add a lot of value for this football team. (The offense) will be a handful for other teams to stop."

Westbrook has 5,995 career rushing yards, but he rushed for just 274 yards and a touchdown last season. He said he "went into last season blind" after rehabbing injuries throughout the offseason and still believes he can be a lead back."