Jeff Haynes/Associated Press

Los Angeles Rams defensive lineman Aaron Donald is expected to miss the team's Week 1 game against the Indianapolis Colts at Los Angeles Memorial Coliseum on Sunday due to his ongoing contract holdout.

On Thursday, Adam Schefter of ESPN reported there's been "no recent progress" toward a resolution, meaning Donald is likely to miss at least the first regular-season game.

The 26-year-old University of Pittsburgh product reported to mandatory minicamp in June but stayed away from the team for the entirety of training camp and the preseason. Now it appears his holdout will extend into the games that actually count.

Last week, Rich Hammond of the Orange County Register noted Rams head coach Sean McVay expressed optimism an agreement could be reached before facing Indy.

"We continue to have a lot of respect for both sides, so we'll keep those (discussions) in-house, but I do feel good about where we're at," he said. "We know that there's progress to be made, but we're optimistic about the direction that we're going and the level of urgency that I think both sides have, to try to get Aaron a part of this so that we can have him playing against the Colts."

Failing to come to terms on a new contract before Week 1 represents a massive setback for Los Angeles.

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Donald has emerged as one of the best players in the NFL since the Rams selected him with the 13th overall pick in the 2014 draft. He racked up 47 combined tackles, eight sacks, five passes defended and two forced fumbles last year, when Pro Football Focus graded him as the league's top interior defender.

His current contract doesn't come anywhere close to matching that production. His $3.2 million cap hit for the 2017 season ranks 73rd among defensive linemen, per Spotrac.

Meanwhile, Donald has remained mostly quietly about the contract stalemate aside from saying in late June he prepared to keep himself in football shape as the process played out.

"I'm just doing my job and just keeping myself how I'm supposed to keep myself, and that will handle itself," Donald told reporters. "It's a fun game but a serious business at the end of the day."

Ethan Westbrooks, Morgan Fox and Tyrunn Walker are among the players who will attempt to fill the void alongside Michael Brockers and Tanzel Smart within the Rams' front seven. The team's defense will struggle to match last season's No. 9 ranking without Donald in the lineup, though.