The larger responsibility is quite a confidence boost, and Brock is determined to help the 49ers (10-4) keep winning as they try to make another run at the Super Bowl a year after a 34-31 loss to Baltimore in the title game.
"You still have to go out there and perform," Brock said. "Not money wise, I just want it all, I want more. I want to go out there and be one of the best. That's what I fight every day for."
The 25-year-old Brock took over as a regular starter in a Week 12 Monday night game at Washington on Nov. 25, replacing the injured Tarell Brown.
Brock had been a reliable playmaker on special teams, and has transferred that success to the defense.
"I'm happy with myself, but I'm not content with it," Brock said. "It's the hard that paid off throughout my whole life. I want to keep it going."