Smith is due $10.15 million for 2013, while Vilma is owed $6 million in the final year of his deal.
The duo were both embroiled in the team's bounty scandal that dominated headlines for the past year.
After tendering several players this offseason and restructuring the contract of linebacker Curtis Lofton, the Saints were left about $6 million over the cap.
New Orleans plans to transition to a 3-4 defense under new coordinator Rob Ryan, which would seem to be bad news for Vilma -- a prototypical 4-3 middle linebacker -- but coach Sean Payton said in February that he believes the veteran can make the switch.
The Associate Press, citing a source, said the Saints also plan to release reserve linebacker Will Herring, who had been with the team for two years.
Information from ESPN NFL Insider Adam Schefter, ESPN.com's Pat Yasinskas and The Associated Press contributed to this report.