SANTA CLARA, Calif. (AP) -- Carlos Rogers has seen the San Francisco 49ers' secondary come a long way in his three seasons with the team, and admits that the revamped unit is playing as well as it ever has during that span.
That's still not quite good enough for Rogers and his crew. The 49ers rank second in the NFL in pass defense, an indication to the Pro Bowl cornerback that they can do a little better.
''Our goal is to be No. 1 back there,'' Rogers said Friday. ''Each and every time we step on the field, we talk about competing, getting the ball back and being the best.''
The 49ers were at their best during last week's 34-3 rout of the Houston Texans, who entered that game with the NFL's fifth-ranked offense. San Francisco limited the Texans to 182 yards passing and made three interceptions, two of them by nickel back Tramaine Brock, who was voted NFC defensive player of the week for his performance.
Brock, making big plays for the second consecutive week in place of injured nickel back Nnamdi Asomugha, returned his first interception 18 yards for a touchdown on the game's third play to get the 49ers rolling toward their most lopsided victory of the young season.
Brock became the sixth cornerback in team history to earn the NFC's weekly honor, and coaches said this week he'll remain in the nickel back role even though Asomugha is now healthy.
''It's pretty obvious he's given us a big lift,'' coach Jim Harbaugh said. ''He's made plays. Even before the two-interception game he was covering, getting PBUs (pass breakups) and tackling. Now he's getting an extended opportunity and making the most of it.''
Brock is complementing a starting secondary that seems to be getting better by the week. The 49ers have allowed an average of 155.5 yards passing over their past four games and just one touchdown pass in their last three games.
Rogers, right cornerback Tarell Brown and strong safety Donte Whitner all returned from a San Francisco defense that ranked third in the NFL last year. The 49ers lost All-Pro free safety Dashon Goldson to free agency, but first-round draft pick Eric Reid has stepped up in his place.
Reid shares the team lead with Brock in interceptions, and the rookie's disciplined play and sure tackling have become factors in San Francisco's defensive equation. Whitner, coming off his first Pro Bowl season, leads the secondary in tackles and continues to set the tone for the unit with his aggressive play.
''It's hard to say a guy is playing better when he had a Pro Bowl season last year, but Donte is playing better,'' defensive coordinator Vic Fangio said. ''He's running our operation back there with a rookie and he's just playing a little faster and with a lot more confidence. He's kind of become a leader of the secondary and a leader on the team.''
Fangio also lauded the play of Rogers, a 2012 Pro Bowl starter who has started every game for the 49ers since joining the team in 2011.
While Whitner - who is in the process of legally changing his name to ''Hitner'' - adds punch to the back end of San Francisco's defense, ninth-year veteran Rogers provides balance with his smooth style, coverage skills and experienced presence.
''Carlos has played well and he's still a very talented player,'' Fangio said. ''He thinks from above the neck. He's very, very good at playing the game intelligently on the run. So we're very pleased to have him and we're lucky to have him.''
Rogers says it's important for San Francisco's secondary to build on its early success over the next month.
The 49ers will face opponents with passing offenses currently ranked No. 22, No. 26, No. 29 and No. 30 in the league over their next four games before a potential NFC showdown at New Orleans and its second-ranked passing attack on Nov. 17.
''Me, Donte and T, we've been doing this going on three years now, and Brock has been here also working with us,'' Rogers said. ''We expect the best. We're all hungry out there to make plays when our opportunity comes. But it's still early in the season and our work is cut out for us. We have a long way to go, a lot of different offenses, a lot of people that are going to challenge us more in the passing game, so we have to continue to improve and be ready.''
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