Lamar Jackson missed practice for a second straight day for the Baltimore Ravens with back and knee issues.
The quarterback was absent on Wednesday but coach John Harbaugh implied it was not a significant concern for the team.
But now, with Jackson absent for a second straight practice session, fears inevitably begin to grow.
The Ravens surprisingly lost last weekend to Cleveland Browns, dropping to 5-3 for the season. This weekend, they take on Denver Broncos.
Jackson is off to perhaps the best start of his career, with a passer rating of 115.4.
Lamar Jackson has missed practice for the Baltimore Ravens for a second straight day
He's thrown for 2,099 yards and 17 touchdowns with only two interceptions. He also has 501 yards rushing.
Last season, the Ravens lost the AFC Championship game to eventual Super Bowl winners Kansas City Chiefs.
But this season, with Jackson boosted by the arrival of running back Derrick Henry, the Ravens have been many people's pick to go all the way this time around.
Speaking after Sundays loss, Jackson said: 'This is the NFL. Any given Sunday a team can be good. We just got to play better all around.
'We didn't make the plays. We didn't make the calls to win the game, left a lot of opportunities out there.'