Portland Timbers captain Liam Ridgewell briefly returned to the pitch last week after missing three weeks with a quad injury, but immediately re-injured his quad in his first day back in training.

Timbers coach Caleb Porter said that Ridgewell will now miss the next 6-8 weeks as he once again recovers from a quad injury. Ridgewell has made just nine starts this season as he has dealt with multiple injuries.

"Obviously, when you have your best defender and your captain and a key guy, you would like him on the pitch and in training and around the team all the time," Porter said. "It's not ideal. It does happen, but the re-injuries, that's one that doesn't happen a lot and you have to start to ask some questions... These are things we have to evaluate, we have to analyze."

Ridgewell is not the only Timbers player currently sidelined with an injury.

Timbers midfielder Diego Chara is out four weeks with a hamstring injury, defender Amobi Okugo is out 4-6 weeks with an MCL sprain and winger Jack Barmby remains sidelined with a calf injury.

The onslaught of injuries come at a time when the Timbers are already dealing with a depleted roster due to the 2017 Gold Cup. David Guzman (Costa Rica), Alvas Powell (Jamaica) and Darren Mattocks (Jamaica) have all joined their respective national teams ahead of the Gold Cup and won't be available to play when the Timbers take on the Chicago Fire at home Wednesday.

With the Gold Cup absences and the injuries, Porter said that the club will only have 17 players available for Wednesday's game.

Porter said the club is evaluating all the factors that could be leading to the growing list of injuries, including the club's training regimen and use of sport science.

But Porter also said that soft-tissue injuries are not uncommon around MLS, particularly in windows where clubs are dealing with compacted schedules, tough travel and difficult weather conditions.

Porter also said that the club works with its fitness coach, athletic trainer and sports science staff to plan out every training session and determine what type of load players can handle. The Timbers monitor the heart rates of every player in training and make adjustments to the workloads of individual players as needed.

"I can't imagine there's a club that's more through in analyzing all that stuff," Porter said. "But when you get guys injured like we have and when you get re-injuries, there has to be some accountability as well and you have to look at things. Trust me, we're looking at everything."

-- Jamie Goldberg | jgoldberg@oregonian.com

503-853-3761 | @jamiebgoldberg