Anthony Barr’s return to the Vikings will have to wait at least a week.

The linebacker has been ruled out for Sunday’s regular-season opener at Cincinnati after missing much of training camp because of a knee injury. Barr returned to practice on a limited basis Wednesday, but had soreness in the knee on Thursday and did not take part in practice. Barr missed 14 games last season because of a torn pectoral muscle suffered in Week 2.

His absence means that Blake Lynch is likely to play in the base defense alongside Eric Kendricks and Nick Vigil. Kendricks and Vigil almost certainly will stay on the field in the nickel defense.

The Vikings also declared first-round left tackle Christian Darrisaw as out. He has yet to take part in a full practice since training camp opened and veteran Rashod Hill likely will be the starter at left tackle for several weeks.

Sean Mannion, who was signed to the Vikings’ practice squad after being let go by Seattle in the final cuts, will serve as the backup quarterback on Sunday to Kirk Cousins. Mannion was the backup for the past two seasons with the Vikings. Kellen Mond was drafted in the third round last spring but the Vikings don’t feel the quarterback is ready to play in a game.

The Vikings have to promote Mannion from the practice squad and can return him to that unit on Monday. However, that move can only be made twice in a season before Mannion will have to be signed to the 53-man roster.