SAN JOSE, California -- Portland Timbers captain Liam Ridgewell suffered a hamstring injury in training Friday and could miss the next 4-6 weeks, Timbers coach Caleb Porter confirmed Sunday.

Ridgewell was expected to be a key starter for the Timbers when they faced the San Jose Earthquakes Sunday at Avaya Stadium, but the injury forced Porter to reevaluate his lineup ahead of the game and will leave the Timbers short-handed on defense in the coming weeks.

"We prepared all week to deal with the way San Jose was going to play," Porter said. "We trained all week with Ridgy in there... and on our last prep day at the end of training, he goes down."

Ridgewell is the latest player on Portland's back line to suffer an injury.

Timbers left back Chris Klute (meniscus surgery) is still working his way back from injury and left back Andy Thoma is sidelined six weeks with a knee injury.

With the injuries, Zarek Valentin is the only viable option that the Timbers currently have at left back, though that could change when Jack Barmby, who is capable of playing left back, arrives in Portland this week.

Valentin started in place of Ridgewell Sunday as the Timbers fell 2-1 to the San Jose Earthquakes.

"I thought he did well going in there," Porter said. "He's not a natural left back, but with Thoma and Klute both out, he's the next guy. He's the only option at this point."

Ridgewell discussed his injury on Twitter Sunday.

Gutted to missing out the game today and next few. Felt my hamstring Friday. Glad luck to the boys. Keep this run going ⚽️🇺🇸 — Ridgy 6 (@liam_ridgewell) March 13, 2016

-- Jamie Goldberg | jgoldberg@oregonian.com

503-853-3761 | @jamiebgoldberg