In addition to Jack, who is out with an ankle injury he aggravated last week, tight end Tyler Eifert (neck) and safety Jarrod Wilson (hamstring) will not play. Right guard A.J. Cann is questionable because of a shoulder injury.
Jack has been the Jaguars' best defensive player this season. He's third on the team with 41 tackles despite missing one full game and parts of two others with the ankle injury, and also has two pass breakups and a sack. Dakota Allen will take his place in the lineup.
Eifert has played in every game and has 11 catches for 93 yards and a touchdown. He originally hurt his neck against Cincinnati in Week 4. Wilson missed three games with the hamstring injury, came back in Week 5, and aggravated the injury last week against Detroit. Brandon Watson will start in his place.
The Jaguars do get kicker Josh Lambo back this week, however. He missed the last four games with a hip injury. He has been with the Jaguars since the 2017 season after getting cut by the Chargers. He has made 74-of-78 field goal attempts (95 percent) in his three-plus seasons with the Jaguars, including 11-of-12 from 50 or more yards.