"Early in the third quarter Sunday, Frank Gore took a handoff through the middle of the Cardinals' defense, picked up terrific blocks by guard Mike Iupati and wide receiver Michael Crabtree and scooted into the end zone for a 37-yard touchdown.

The 49ers led 19-7, and the offense appeared to be in excellent position to do what it does best: Grind away at the opposing defense and game clock with its big offensive line and running game.

It didn't happen that way. Gore carried the ball only two more times the rest of the game and wasn't on the field for the team's final two snaps.

On Monday, coach Jim Harbaugh explained why.

"He's got some things," Harbaugh finally said after prodding. "He's not 100 percent. We have other backs that got carries in the second half.""