Portland Timbers center back Larrys Mabiala suffered an ankle injury during the first leg of the Western Conference Championship series against Sporting Kansas City Sunday.

The Timbers are still evaluating Mabiala to determine the severity of the injury.

Mabiala, who has been a mainstay on the backline for the Timbers this year, was stretchered off the field in the 19th minute after going down with a non-contact injury.

It initially looked as if the injury might be more serious than just a twisted ankle.

Timbers coach Giovanni Savarese said Monday that the club was still evaluating Mabiala to determine whether he could feature in Thursday's second leg game at Kansas City. Mabiala had to be helped off the field Sunday and did not put any weight on his ankle before being stretchered off. It would be a surprise to see Mabiala return to the field in time for Thursday's game.

"He's still being evaluated," Savarese said. "We'll find out more tomorrow, but right now we don't know much, except that he twisted his ankle... We're doing everything possible to try to get him to the game."

Timbers midfielder Andy Polo, who was not in the 18 Sunday due to a calf strain, participated in a portion of training Monday and is expected to return to full training Tuesday. Given that timeline, Polo could be available for Thursday's game.

"Polo trained well today," Savarese said. "He's looking like he's going to be able to be full tomorrow."

Savarese said the club is also still evaluating forward Samuel Armenteros, who was unavailable for Sunday's game due to back spasms.

-- Jamie Goldberg | jgoldberg@oregonian.com

503-853-3761 | @jamiebgoldberg