Asomugha, who joined the 49ers following his release by the Philadelphia Eagles, has been rewarded for his efforts with the third cornerback slot in the 53-man roster.
"I've just been going out and just working each day," he told the San Francisco Chronicle.
"I know my abilities, I know I can help the team. It's just letting everything unfold, playing as best as I could."
Asomugha made 55 combined tackles for the Eagles last season.