The 30-year old Argentine attacker, who joined the club in March this year, is now out of contract but after the Sounders' Conference semi-final loss to Real Salt Lake during the week told reporters he is likely to be back in 2012.
"Yeah, I hope for the same. I think next week we're going to finish everything so I can be here," he said.
"I'm very confident that everything's going to work out."
Rosales was injured for the two semi-final legs but managed 26 appearances for Seattle in his debut season, scoring five goals.