Seattle Sounders center back Chad Marshall will have surgery on his knee meniscus and will miss Thursday's second leg of his club's Western Conference Semifinal series against the Portland Timbers (10:30 pm ET | FS1, FOX Deportes, TSN, TVAS), coach Brian Schmetzer revealed Tuesday.

“Marshall is having surgery this morning for a meniscus injury and I will give you further updates once the surgery is successful and he’s back on his feet," Schmetzer told reporters at training on Tuesday.

Midfielder Cristian Roldan, meanwhile, is day-to-day with a hip flexor injury, Schmetzer said. Both players departed late in the first half of Sunday's first leg, a 2-1 Timbers victory.

The 34-year-old Marshall has 401 total MLS regular season appearances, and has started in all but four of the Sounders' regular season and playoff matches in 2018. The club did not reveal whether he could potentially be available should the team reach the Western Conference Championship later this month.

He was replaced Sunday by Panamanian international Roman Torres, who had been his primary center back partner in 2017 but saw his time reduced in favor of Kim Kee-hee in 2018. Torres and Kim have started only two matches together, a 1-0 win at San Jose on July 25 and a 3-0 loss at the LA Galaxy on Sept. 23.

Roldan will be a gametime decision, Schmetzer said. The midfielder played all but seven minutes of Seattle's 2018 regular season campaign, but had to exit after just 31 minutes on Sunday.

Ari Liljenwall provided reporting for this piece.