Portland Timbers midfielder Diego Chara broke a bone in his foot while teammates Darlington Nagbe and Larrys Mabiala also left Monday's playoff game with injuries.
The Timbers managed a goalless draw in their first leg at the Houston Dynamo -- thanks in part to a controversial video review -- but they are facing an injury crisis ahead of the return leg on Sunday.
Chara went down on a non-contact play at the end of the first half and was taken off the pitch on a stretcher. He was on crutches after the game with his foot in a boot, and Timbers coach Caleb Porter said he had broken the fifth metatarsal bone in his right foot.
Chara will definitely miss the second leg, while Nagbe and Mabiala could be in a race to return for the game in Portland. Mabiala picked up a hip injury in first-half stoppage time, and Nagbe left the game before the hour mark with a tight hamstring
The top-seeded Timbers are already without forward Fanendo Adi, winger Sebastian Blanco and midfielder David Guzman.
Blanco was a late scratch after suffering second-degree burns on his right foot in a cooking accident this week, while Guzman sprained his knee in the regular-season finale. Adi, who scored 10 goals this year, has been out with a hamstring injury since early August.
Timbers star Diego Valeri said Chara's injury in particular was "bad for us."
"Diego is very important for us in the middle. We lost David Guzman, Sebastian Blanco, too. We have [Fanendo] Adi [out]," Valeri said. "So we have a couple of injuries but we have a good team so we have to fight next week and win at home."
However, Porter remained confident that the Timbers had to depth to continue competing in the playoffs. Roy Miller, Amobi Okugo and Jeremy Ebobisse came in an substitutes to replace Portland's injured trio on Monday.
"We're where we're at because of our depth," Porter said. "I think that showed a lot of mettle from our guys to be able to adjust because it's not really the type of game that we're used to playing."