Lamar Jackson has tested positive for coronavirus, disrupting the Baltimore Ravens' preparations for the new NFL season.
Ravens coach John Harbaugh revealed on Wednesday his quarterback was missing the team's first practice of training camp.
Former NFL MVP Jackson reported to camp last Thursday but only returned a positive result on Tuesday, with running back Gus Edwards also confirmed as a case.
Harbaugh, who would not reveal how long the pair would be sidelined for, said: "It's just part of the deal. It's just the way the world is right now.
"It's no different than if somebody gets an injury – you tweak an ankle and you're out for some number of days. It's just part of football.
"To me, whenever you have a problem or whenever something comes up like that, you embrace it and you almost kind of rejoice in it because it's an opportunity to improve somewhere else."
Trace McSorley and Tyler Huntley took the majority of snaps in Wednesday's practice, with Robert Griffin III waived by Baltimore in January.
Griffin started for the Ravens on both occasions Jackson was missing over the past two seasons, including when he previously tested positive for COVID-19 ahead of the Week 12 trip to the Pittsburgh Steelers in 2020.
In a 19-14 defeat, Griffin completed seven of 12 passes for 33 yards and an interception.
McSorley came off the bench to supply their sole touchdown pass, connecting with Marquise Brown for a 70-yard score from one of only two successful throws.
Across the other 15 games, Jackson regressed from his MVP year, his passer rating falling from 113.3 to 99.3 as 36 touchdowns and six interceptions became 26 TDs and nine picks.
He still passed 1,000 rushing yards, however, and scored seven times with the ball in his hands.