Keller to play on for one more year
"In these two years with the Sounders, I've been very happy with the form of myself and the team," Keller, 41, told the Sounders' website.
"Throw in the fact that Portland and Vancouver are coming into the league, and there was no question that I wanted to play one last season.
"My mind's great, my body feels great, and so I feel this can be a great and successful season for the Sounders and myself."
Before signing with Seattle in 2008, Keller spent much of his career in Europe's top leagues, including the English Premier League, Spain's La Liga and Germany's Bundesliga.
Keller has been a member of four U.S. World Cup squads and has been capped 102 times, a record for a U.S. keeper.