Idzik, who was fired by the Jets in late December, will not have a role in player evaluation but will work with the team's salary-cap department, the source said. Idzik will work alongside Tim Walsh, the team's director of football administration and the person responsible for managing the salary cap.
The Jaguars have the most cap space of any team in the league (approximately $65 million) heading into the 2015 league year, which begins March 10.
Idzik was the Jets' GM from 2013-14, during which the team went 12-20. Among his moves that failed to work out was trading cornerback Darrelle Revis and failing to land a receiver in the 2014 draft class that may turn out to be the best in NFL history. The Jets drafted three receivers in 2014 -- Jalen Saunders, Shaquelle Evans, and Quincy Enunwa -- and they played in a combined four games.
Jets owner Woody Johnson fired Idzik and coach Rex Ryan on Dec. 29. Prior to joining the Jets, Idzik spent six seasons as Seattle's vice president of football administration. Jaguars coach Gus Bradley was the Seahawks' defensive coordinator from 2009-12.