Seattle Sounders FC placed goalkeeper Terry Boss on the disabled list Friday due to a concussion.
Boss, 30, will miss the remainder of the year. He has made four starts in all competitions with four victories, the most recent being a 1-0 shutout victory at Monterrey on Aug. 23 in the CONCACAF Champions League.
Boss sustained the concussion while playing for the Puerto Rico national team in a 2012 World Cup qualifier against St. Kitts and Nevis on Sept. 2.
Seattle hosts Real Salt Lake in an MLS match on Saturday.