The contract is worth a reported $3.875 million and carries a cap hit of $1.9375 million.
The Lightning had an arbitration hearing scheduled for Friday.
Namestnikov, 23, is coming off the first full season of his young career, registering 14 goals and 21 assists in 80 regular season games in 2015-16. The Russian centreman has earned a total of 23 goals and 28 assists in 127 career games over three seasons with the Lightning.
July 26, 2016