Seattle played the last 26 minutes with 10 men and was held to a scoreless draw at home by lowly Houston on Wednesday, leaving the Sounders' MLS playoff hopes in jeopardy.

Victory would have all but sealed Seattle's playoff berth, but with two regular season games to play and six Western Conference teams to make the postseason, they are four points ahead of seventh-placed Portland.

Houston, last in the West, came closest to scoring in the 30th minute, when Will Bruin's shot was deflected by Seattle goalkeeper Stefan Frei onto a post and away to safety.

Seattle's Osvaldo Alonso was sent off with a straight red card following a scuffle with Bruin midway through the second half.