"They're going to have me learn the SAM position. It'll be the biggest challenge of my football career," Posluszny said, via the team's official Twitter account.
Posluszny earned 133 tackles in each of the past two seasons patrolling the middle of the Jacksonville defense. Pro Football Focus ranked the 32-year-old veteran fourth among linebackers for the 2016 season.
Moving Posluszny is about making room for Jack to see the field more. The athletic second-round pick saw just 230 snaps his rookie season, according to Next Gen Stats.
With Jack patrolling the middle, Posluszny moving to the outside and Telvin Smith on the weak side, the Jaguars will own a rangy linebacker group. With the additions of corner A.J. Bouye, tackle Calais Campbell and safety Barry Church, Jacksonville has the potential to boast a playoff-caliber defense in 2017.