Portland Timbers midfielder Diego Chara and defender Amobi Okugo will each be out at least four weeks with injuries.
Timbers head coach Caleb Porter said on Thursday that Chara suffered a hamstring injury in Sunday's 2-2 draw against the Seattle Sounders and will miss four weeks.
Okugo, who sprained his MCL in the same game, will be out the next 4-6 weeks.
Meanwhile, Porter indicated that defender Liam Ridgewell will not be available for Portland's match against Sporting Kansas City on Saturday as he recovers from a quad strain.
"It's not progressing as quickly as we thought," Porter said of Ridgewell. "He's still having some discomfort in that quad."
Midfielder Darlington Nagbe, who was also injured against Seattle, is questionable for Saturday's game, while Porter said winger Jack Barmby -- injured Tuesday during training -- will be out "another couple of weeks."