As mysteries go, this one has to rank right up there.
When the San Francisco 49ers signed running back Brian Westbrook in mid-August, he figured to play a prominent role in a numbers of ways – in the same backfield with Frank Gore, as a substitute when Gore needed a breather, as a valuable third-down back, as a slot receiver.
Instead, Westbrook has become a missing person. He's touched the ball just 10 times in 10 games this season and has played 36 snaps.
It's possible all that could change Monday night when the 49ers play the Arizona Cardinals in a nationally televised game. Offensive coordinator Mike Johnson said Friday that, although there won't be any lineup changes on offense, it's likely more players will get opportunities to play, including Westbrook.
"I think you may see some guys rolling in and out as the game goes," Johnson said. "We'll see how certain things go at certain spots, but we're starting out the same way."
Johnson said a key factor is that Westbrook is more familiar with the playbook, making him a possible contributor in several ways.
"He's at that point now," he said. "He's at that point where he is now understanding everything that he has to do."
Hard to believe it's taken this long for Westbrook to comprehend the playbook – Philadelphia Eagles coach Andy Reid called Westbrook one of the smartest players he's ever coached – but Johnson said the plan was to get him involved last Sunday against the Tampa Bay Buccaneers.
"There was a plan last week to use him in the run game," Johnson said. "The first time we gave him the ball in the run game, we get a holding penalty. So now we're second and 17, so that was a series that he was going to go in the game and he was going to run. But certain things happen that you have to change, and you do certain things and you get away from that. But he's at the point now where he's comfortable."
Johnson said putting Westbrook in the game means taking out Gore or tight end Delanie Walker, who has been a solid contributor and a matchup problem for opponents.
"When you put Brian Westbrook in the game, it's a different matchup problem," he said. "Now you have to add a whole new part of an offense that we haven't had a training camp to install. So you see him doing certain things in small pieces.
"But to utilize both Frank and Brian, those things have to be taught and they have to be detailed in a longer period of time. When you do that, it takes one of those guys off the field and I'm just trying not to take Frank off the field unless he's tired. We need Frank Gore to be who he is."
Maybe that will change Monday night.
INJURY UPDATE: Players got the day off for Thanksgiving but resumed practice Friday. Safety Dashon Goldson (ankle) and kicker Joe Nedney (right knee) did not practice, while wide receiver Josh Morgan (shoulder) was a limited participant. Full participants were cornerback Nate Clements (ankle), tackle Anthony Davis (ankle), tight end Vernon Davis (ankle) and Gore (ankle).