Raiders running back Rashad Jennings calls himself a "fitness nut."

And some of his teammates looked at him as though he was crazy on Monday.

There he was a day after running the ball 14 times catching eight passes and blocking a punt leaving the locker room with his bike to ride the 20 minutes or so home. Jennings also sleeps in a hyperbaric chamber to increase blood oxygen and promote healing and regularly sees a chiropractor and an acupuncturist.

Jennings also calls himself a "nerd."

Again he has a point. In college he taught himself to write with each hand - "just for the hell of it." He also learned every magic trick there is and how to play guitar in his spare time from class and football. Currently Jennings visits companies like Facebook and Pandora to learn more about the business world.

Jennings and the Raiders will probably call him their lead running back Sunday night against the Chargers.

Starter Darren McFadden missed a third straight day of practice Friday with a hamstring injury. (McFadden even hinted that the team may hold him out for two games to take advantage of more recovery time with the bye in Week 7.)

Jennings is ready and has worked hard since training camp as if he was already the starter.

"When opportunity presents itself it's too late to prepare for it" Jennings said.

Raiders offensive coordinator Greg Olson wasn't sure Jennings was prepared to be the No. 2 running back when the team signed the 28-year-old free agent in April. Jennings averaged 2.8 yards per carry last season for Jacksonville where Olson was the assistant head coach and quarterbacks coach.

"To be honest with you I wasn't sure how it was going to work him coming here" Olson said. "For whatever reason he's a better player here."

Was it the change of scenery or the new system maybe California weather? Olson has no idea.

"He seems to be a more focused player a tougher player a tougher runner" Olson said. "I see a tougher runner than I saw a year ago so hopefully he'll continue because I thought he ran the ball hard last week. He made people miss and he also ran some people over. That was real encouraging for me."

Jennings who easily beat out rookie Latavius Murray and Jeremy Stewart for the No. 2 running back job didn't smile when he heard Olson's assessment.

"I have nothing to say about what's in the past" Jennings said. Later he added that he has the "same approach" now that he had in Jacksonville.

The 6-foot-1 231-pound Jennings ran 14 times for 45 yards and had eight catches for 71 yards against the Redskins on Sunday and as head coach Dennis Allen said was a "thumper." On one 3rd-and-8 play that led to a score Jennings caught a 3-yard pass from Matt Flynn made one defender miss and then plowed two others for 12 yards and the first down.