Vannett (back) is inactive for Sunday's game against the Raiders.
Vannett's presence on the inactive list comes as a surprise after coach Pete Carroll said just two days earlier that the third-year player would be available for the London game. With Vannett sidelined for at least this week and Will Dissly (knee) on injured reserve, the Seahawks are suddenly thin at tight end. Darell Daniels and Tyrone Swoopes -- both of whom were members of Seattle's practice squad less than two weeks ago -- will represent the team's only options at the position in Week 6.