SANTA CLARA -- Cornerback Tramaine Brock and the 49ers agreed to terms Friday afternoon on a four-year, $16 million contract extension that includes $7 million in guaranteed money, a source told CSNBayArea.com.
Brock will make his first career start Monday night when the 49ers face Washington in place of Tarell Brown, who is out indefinitely with a ribs injury.
Brock, a fourth-year player, has played well in seven games after taking over for Nnamdi Asomugha as the 49ers' No. 3 cornerback. He was named NFC Defensive Player of the Week after recording two interceptions, including one he returned for a touchdown, against the Houston Texans on Oct. 6.
In 2011, Brock opened the season as the 49ers' No. 3 cornerback. He recorded interceptions in his first two games before missing time with a hand injury. Chris Culliver replaced him, and Brock did not get his job back until this season when Asomugha left the lineup with a knee injury. After Brock took over as the No. 3 cornerback, the 49ers released Asomugha.
On Monday, Brock will be on the field as a starter.
When asked about that change of roles for Brock, 49ers defensive coordinator Vic Fangio said the biggest adjustment will be remaining on the field for every down.
"I think the change comes in that he went from not playing to being in the nickel, which is a part-time job where you’re in and out and you usually get a break of at least two or three plays or longer depending on the game you’re in," Fangio said. "And now the change comes, it’s amped up another level. He’s in there every play.
"He’s just got to be ready to play every play not knowing he’s got built in breaks when we’re in base like he had for the first however many games he was playing. There is a change, but it’s just got to be a mental adjustment for him.”
Brock's contract extension indicates that the club views him as a starter next season. It's a contract similar to what the 49ers were believed to be willing to pay Brown, who is in the final year of his contract.