He was listed as questionable Friday after he was limited in practice for the third straight day with a sore right shoulder. Coach Chuck Pagano gave no indication to the extent of Luck's participation or how much Luck has thrown this week.
Still, Pagano is hopeful Luck will start against the Jaguars.
If Luck doesn't play, backup quarterback Matt Hasselbeck is expected to start. And on Friday, the Colts signed quarterback Josh Johnson, who most recently spent time with Cincinnati and the New York Jets this preseason.
Luck, who suffered the shoulder injury in last week's 35-33 win at Tennessee, hasn't missed a start since he joined the league in 2012.