SANTA CLARA – On the second snap of Sunday's 49ers game against New England, J.T. O'Sullivan nearly connected with tight end Delanie Walker on a play that would have resulted in a huge gain if only Walker had hung on to the ball.

Why did Walker have so much room to run? Offensive coordinator Mike Martz on Thursday pointed to fellow tight end Vernon Davis.

"Did you see how wide open (Walker) was?" Martz asked. "They were all running with Vernon. There were three guys chasing Vernon down the field. Had we completed that, (Walker) may have been in San Diego before he stopped."

Like Davis' blocking ability, it was an example of an offensive contribution that doesn't end up on a stat sheet. That Davis attracts so many defenders deep downfield has helped the 49ers open up other areas of the field, Martz said.

Davis, however, isn't content with being a decoy. He was drafted with the sixth overall pick in 2006 to be a big-play tight end. But he has just five catches through five games this season and has yet to find the end zone.

Last year, he caught at least one pass in every game he started. On Sunday, he was held without a reception for the second time this season.

"I want to help out as much as I can as far as catching passes," he said. "That's what I'm here to do – make plays. That's what I want to do. I guess there's really nothing you can do if you've got two or three guys running with you. The only thing you probably can do is come up with different ways to give me the ball or something like that."

One reason Davis isn't running more pass routes is because he's being used in pass protection. Martz's offense relies on the quarterback taking deep drops and making long passes. That also exposes the quarterback to the pass rush, and so far the 49ers have given up more sacks (20) than any other team.

Martz called Davis an "unusual blocker" and said he didn't know if there was a better blocking tight end in the league. And Davis, who complained last year that his blocking duties were trumping his receiving opportunities, said he has been asked to pass block even more this season.

"I never did pass protection as much … as I'm doing now," Davis said.

Is that a surprise? "A little bit," he said. "I definitely didn't expect it."

Martz preached patience as far as Davis' involvement in the passing game. He said he's using Davis as he once used Ernie Conwell with St. Louis, except Davis is being asked to do something very unorthodox: run receiver-like routes from the tight end position.

"He'll have his opportunities for sure," Martz said. "There's nothing wrong with Vernon. All those things are an indication of nothing other than we're learning this offense, and as we're moving along, we're trying to win games."

Et cetera – Running back Frank Gore and cornerback Walt Harris were back at practice after having Wednesday off. Safety Michael Lewis (elbow) practiced on a limited basis. Tackle Jonas Jennings (shoulder) and linebacker Manny Lawson (hamstring) did not practice.

• Perhaps anticipating they will be without halfback Brian Westbrook (ribs) Sunday against the 49ers, the Eagles this week moved Tony Hunt from fullback to halfback and Dan Klecko from defensive tackle to fullback.

• Linebacker Roderick Green has not practiced this week because of stomach flu, increasing the likelihood that Tully Banta-Cain will be active for the second consecutive week.

Read Matthew Barrows' 49ers blog at www.sacbee.com/ninersblog.