Seattle Sounders forward Jordan Morris has been sent back to Seattle by the U.S. national team as he continues to deal with a strained hamstring, forcing him out of the USMNT’s two upcoming CONCACAF World Cup Qualifying matches and putting him in question for the Sounders’ postseason push.

Morris suffered the injury during the first half of the second leg of the Western Conference Semifinals against FC Dallas on Sunday, just hours after he was named to head coach Jurgen Klinsmann’s 23-man roster for the two Hexagonal matches. Morris watched from the bench as the Sounders ultimately clinched the series before he left Monday to join the USMNT ahead of a huge matchup against Mexico on Friday at MAPFRE Stadium in Columbus, Ohio.

Morris was evaluated by U.S. team doctors and ruled out of the Mexico match and another crucial road clash against Costa Rica next week in San Jose. He was replaced on the roster by LA Galaxy forward Alan Gordon,

It’s unclear how the injury will affect Morris’ availability when the Sounders open the next round of the 2016 Audi MLS Cup Playoffs. The Sounders will host the Colorado Rapids in the first leg of the Western Conference Championship on Nov. 22 before closing the series in Colorado on Nov. 27.

Morris will have roughly two weeks to recover from the injury before the series opens, and the Sounders will need his help to reach their first-ever MLS Cup Final. Morris led the Sounders with 12 goals during the regular season and picked up his first career postseason assist in the first leg against Dallas on Oct. 30.

Morris has been remarkably durable during his rookie season, appearing in 32 regular season games for the Sounders while also balancing sporadic duty with the USMNT. He last appeared for the U.S. in an international friendly against Cuba on Oct. 7, his fourth cap of 2016 and the 12th of his career.

The Sounders are expected to return to training on Tuesday at Starfire Sports in suburban Tukwila, while Morris will learn Thursday if he has been named the AT&T MLS Rookie of the Year.