SANTA CLARA, Calif. -- Tramaine Brock will get another opportunity to show he belongs as the No. 3 cornerback of the San Francisco 49ers on Sunday.Brock excelled last week at St. Louis when he played for an injured Nnamdi Asomugha. He is still coming back from the injury. Because Brock played so well, there is no rush. If Brock continues to play well, I could see a scenario in which he stays the No. 3 cornerback. Younger legs and better tackling would be Brock's ticket over Asomugha.