SEATTLE -- Eric Reid's phenomenal start to his career is on hold. The 49ers' rookie safety has been ruled out from returning to Sunday's game because of a concussion he sustained on a second-quarter tackle.

Reid appeared to knock himself out when he used his left shoulder and head to stop Sidney Rice on a 13-yard reception 1:49 before halftime. The 49ers medical staff tended to Reid for several minutes before he walked off the field and appeared to mouth: "I'm good."

Rice was assessed a 15-yard taunting penalty for celebrating his catch, and that Seahawks drive resulted in a punt for the final play of the first half.

Reid has started his 49ers career with an interception in each of his first two games. He tracked down a third-down bomb at the 49ers' 24-yard line to stop the Seahawks' second series.

Reid was covering Golden Tate deep one-on-one before hauling in the 46-yard pass by Russell Wilson, who started 0-of-6 passing.

The last rookie to record an interception in each of his team's first two games: Nate Allen of the Philadelphia Eagles in 2010.