The Seahawks had been the dominant side in the NFC West during the 2000s, but the 49ers have won the division for the last two seasons.
The safety told the team's website: "I'm excited for another opportunity to show how good we are. Both teams have made this a great rivalry and we're looking forward to the challenge.
"We're going to focus on what we can control and get back to the basics. I watched [the 49ers' game against the Green Bay Packers] until like half time, then I feel asleep."
Cornerback Richard Sherman added: "It's always one game at a time, and this is a perfect example of it. It's just another game, another chance for us to put some good tape out there and play disciplined."
The two teams won their home games against each other last season.