49ers' Whitner up for the challenge against Miller

SANTA CLARA, Calif. (AP) - This weekend, safety Donte Whitner draws the daunting task of trying to shut down Seattle Pro Bowler Zach Miller.

It could emerge as one of the more important matchups Sunday in San Francisco's season opener against the defending NFC West champion Seahawks - and help determine the outcome of coach Jim Harbaugh's NFL debut. The 49ers need a reliable cover man after the departure of Manny Lawson, and Whitner is determined to become that guy for his new team.

Seattle surely will try to expose him.

"I'm looking forward to it. I'm challenging myself. I'm challenging my teammates," Whitner said. "It's going to come down to some one-on-one battles with me and him."

Miller and Whitner aren't strangers, either. They share an agent and went through the free agency process together this summer after the lockout, only to wind up in the same division.

Miller, the athletic and talented tight end, certainly will be eager to make a statement in his debut for the Seahawks' overhauled offense. He will be back in the Bay Area, too, following four seasons with the Oakland Raiders. He led the Raiders in receiving the past three years but Oakland was unable to keep him in free agency.

Whiter hopes his matchups with Vernon Davis during practice have helped prepare him for Miller, who has an uncanny ability to gain extra yardage after the catch with his speed.

"He's a really good tight end in this league, but I think I see the best tight end in the National Football League here each and every day," Whitner said.

The 26-year-old Whitner, the eighth overall pick out of Ohio State in 2006, ranked fifth in the NFL with 140 tackles last season for Buffalo and also had one forced fumble, an interception and half a sack.

"Donte, for sure, is a big deal, to have him with his experience and background and playmaking and all of that," Seahawks coach Pete Carroll said.

But Whitner struggled in coverage for the Bills, allowing 38 completions on 53 attempts for 501 yards and 10 touchdowns, according to game charting by STATS LLC. Whitner was the targeted defender on more TD passes than any other player in the league in 2010.

"He's a pretty solid player," Seattle quarterback Tarvaris Jackson said.

Not exactly a ringing endorsement of Whitner's skills.

He heard the skeptics before in Buffalo. That fuels him all the more.

"I usually read a lot of the blogs and sometimes even fans," Whitner said. "They might not even know which defense you were in, you just might be in the area. It might not be your responsibility but they form their opinion based on what they see from the cut ups. Just a little extra motivation for myself."

Another 49ers defender, rookie Aldon Smith - one of San Francisco's three outside linebackers - is raw and has yet to develop his coverage skills.

Miller will no doubt take note. He had 60 catches for 685 yards and five touchdowns last season in his final year for Oakland.

"I watched what he did in Oakland and we're just trying to make sure we play to his strong suits, try to get him the ball and let him run after the catch," Jackson said. "In Oakland he was pretty good after the catch, so just try to get him the ball and let him do what he do."

The 49ers ranked 20th in the NFL for pass defense in 2010. Whitner hopes to help change that in a revamped defense with many new faces, while also taking on a leadership role for the unit.

Whitner committed a pass-interference penalty late in the first quarter of a 30-7 preseason loss to the Texans on Aug. 27 that helped set up Derrick Ward's 1-yard touchdown run that put Houston ahead for good.

He doesn't pretend to have everything down just right in defensive coordinator Vic Fangio's system. As Harbaugh so likes to say, "it's a process."

Whitner hopes to be an active, attacking, flying-around-the-field defender like Steelers star Troy Polamalu - the NFL's Defensive Player of the Year in 2010.

Perhaps in time. The 49ers just want Whitner to be himself.

"He's a versatile guy. He can cover, he can play the deep zones, he's smart," Fangio said. "We expect him to be kind of the quarterback of our secondary, and we're very pleased to have him. He just needs to be the safety for us. He doesn't need to be the safety for somebody else."

Notes: WR Michael Crabtree, who missed his third straight preseason with a broken left foot that required surgery, ran routes at full speed and looked healthy. Harbaugh wouldn't say whether Crabtree will play Sunday. ... CB Shawntae Spencer (hamstring) and S Reggie Smith - recovering from recent surgery to repair the meniscus in his knee - also returned to practice.