With fourth and goal, St. Louis needed a touchdown to take the lead but Frerotte, who had replaced Mark Bulger in the first quarter, couldn't handle the snap and the Seahawks tackled him and took over on downs.
Matt Hasselbeck passed for 249 yards and a touchdown in the third straight victory for the Seahawks (7-4).
Deion Branch caught five passes for 92 yards and a touchdown, and Bobby Engram caught seven for 70 yards.
Frerotte passed for a touchdown and was intercepted once after Bulger, who also was intercepted once, left the game with a concussion.
Notable deaths of 2014 [PHOTOS]
Michael Sam cut from the Dallas Cowboys