The deal brings the Islanders closer to the NHL's salary floor of US$48.3 million next season.
It also gives the Devils a little more cap space to try and sign restricted free agent Zach Parise, who is scheduled to go to salary arbitration next week.
Rolston is entering the final year of a deal that pays him a little over $5 million while Hunter is scheduled to earn $2 million.
The 38-year-old Rolson had 14 goals and 34 points in 65 games for the Devils last season.
Hunter was limited to just 17 games because of a torn MCL. He had one goal and four points.