"Near the end of a recent 49ers practice, quarterback Alex Smith and tight end Vernon Davis stood near midfield and simply talked things over. Smith used his right arm to demonstrate where the tight end should change direction. Davis studied the angle of Smith's arm and nodded in approval.

The two have a good rapport -- 37 percent of Smith's career touchdown passes have gone to Davis -- but they need to work out a few kinks in their game.

Their bread-and-butter play, the deep seam route, is no longer a secret. Opponents kept Davis in check earlier this season by greeting him with double coverage any time he came tearing down the middle of the field. The Raiders will be on alert for Davis' signature seam route today at Candlestick Park.

That is why Davis and Smith are making sure that they aren't just a one-route wonder. New offensive coordinator Mike Johnson is helping, too, as the 49ers try to counter the defensive adjustment with a counter move of their own.

"Teams have placed cornerbacks on (Davis), they've placed safeties on him, and they're trying to jam him at the line of scrimmage," Johnson said. "That's where we as coaches and myself, we have to find ways to make sure that teams do not take him away.

"And I think you saw that in the second half of the game against Philadelphia. He is an explosive guy."

Smith and Davis hit on a big one -- a 36-yarder -- against Philadelphia late Sunday. The game circumstances helped open things up. The Eagles led 24-10 at the time, and they gave Davis and other receivers plenty of cushion.

That is when Smith found Davis matched up against safety Quintin Mikell and let it rip on the deep seam."