Misi signed a four-year extension worth $17 million in 2013, per Spotrac. The 29-year-old linebacker has been a member of the Dolphins since the team selected him in the second round of the 2010 NFL draft.
Misi has appeared in all 16 games in a season only once in his career, his rookie year. He's accounted for 329 total tackles in 81 games for the Dolphins. After recording 60 tackles and two forced fumbles in 2012, Misi earned his new deal.
Misi had a career year in 2015, recording a career-high 77 total tackles—the third-most on the team—in 13 games played. He was also second among Miami linebackers, trailing only Kelvin Sheppard's 102.
The former Utah Utes star was set to make $4.275 million next season and $4.175 million in 2017 before becoming an unrestricted free agent in 2018.
Although the Dolphins have not disclosed the details of Misi's restructured deal, they freed up almost $24 million in salary-cap space after releasing veteran wide receiver Greg Jennings and adjusting the contracts of Misi and defensive tackle Ndamukong Suh, per Chris Trapasso of CBS Sports.
Veteran defensive end Mario Williams met with the Dolphins on Saturday, per ESPN.com, so that could be one reason why Miami wanted to create more flexibility. Misi has been a staple in Miami's front seven throughout his six-year career, so his new deal shouldn't be an indictment on his play.