Pat Onstad is the MLS leader in goals-against average, shutouts and wins. (Tony Gutierrez/Associated Press)

Vancouver's Pat Onstad won't play for the Major League Soccer all-star team after straining his back in the Houston Dynamo's 1-0 loss to New England on Saturday night.

Onstad, who plays for Houston, will be replaced by Chivas USA goalkeeper Zach Thornton when the MLS squad takes on English Premier League club Everton on Wednesday night in Utah.

The 41-year-old Onstad ranks first in the league in goals-against average (0.74), shutouts (eight) and wins (nine).

This was the third MLS all-star selection for Onstad, who was added to the roster on Monday by coach Dominic Kinnear.

Canadian Toronto FC midfielder Dwayne De Rosario was chosen to the starting 11 but elected to skip the game in order to play for his club side against the Puerto Rico Islanders in the CONCACAF Champions League the same day.