Seahawks' Sam Darnold has a soft tissue injury and the timeline for his return is unclear

Seattle Seahawks quarterback Sam Darnold has what the team calls a “very unique, soft tissue” glute injury with no set timeline for his return

Seattle Seahawks quarterback Sam Darnold has a “very unique, soft tissue” glute injury with no set timeline for his return, the team announced Monday.

The injury is believed to be short-term and Darnold's hip joint was unaffected, the team said. He has not been placed on injured reserve.

It appears unlikely that Darnold will be able to play Sunday at the Arizona Cardinals. He did not practice on Monday.

Darnold was injured on Seattle’s first series against the New England Patriots last week. He was sacked by Dre’Mont Jones and limped off the field.

Backup Drew Lock replaced him and went 16 of 22 for 187 yards and a touchdown as the Seahawks rallied for a 13-10 victory .

Darnold, 29, did not miss a game last season as he led the Seahawks to a Super Bowl title. He threw for 4,048 yards with 25 touchdowns and 14 interceptions as Seattle won a franchise-record 14 games.