A person familiar with the deal confirmed the extension, which was first reported by Comcast SportsNet California. The person spoke on condition of anonymity Tuesday because the contract can't be signed until the free agency window opens July 5.
Couture is owed $3 million next season in the final year of a two-year, $5.75 million contract. Couture would have been eligible to be a restricted free agent next summer. The person would not say how long Couture's new deal would last but Comcast reported it was expected to be for five more seasons.
The 24-year-old Couture has emerged as one of the Sharks' top players the past two years in all facets of the game, becoming the team's most reliable goal-scorer, drawing the toughest defensive matchups and becoming a leader in the locker room. Couture is expected to become part of the formal leadership group next season, replacing the departed Ryane Clowe as an alternate captain.
Couture has led the team in goals the past two seasons, scoring 31 in 2011-12 and 21 during this lockout-shortened campaign. He is tied for seventh in the NHL with 84 goals over the past three seasons.
Couture has also been a strong post-season performer in his career, helping the Sharks make back-to-back runs to the conference final in 2010 and 2011 and leading the team's playoff charge this season. He has 17 goals and 16 assists in 49 career playoff games.
General manager Doug Wilson has historically done a good job of locking up his star players before they hit the open market, doing deals previously with players like Joe Thornton, Joe Pavelski, Brent Burns and Antti Niemi.
Locking up Couture was one of the biggest items on Wilson's to-do list this off-season as the Sharks try to improve on this year's playoff run, which ended with a Game 7 loss in the second round at Los Angeles.
The Sharks would also like to sign Pavelski to a new deal before he can become an unrestricted free agent in 2014 and want to bring back unrestricted free agent forward Raffi Torres, among others.