The Anaheim Ducks have signed defenseman Simon Despres to a five-year extension, the team announced Friday.

The deal is worth $18.5 million, an average of $3.7 million per season, a source told ESPN.com.

"I'm happy it's done," Despres said after practice Friday. "I'm happy for me and my wife. It's going to be an exciting time for the next five years, and I'm looking forward to winning a couple of Stanley Cups."

Despres has been an outstanding contributor to the Ducks' lineup since the club acquired him in a March trade with the Pittsburgh Penguins for defenseman Ben Lovejoy. Despres would have been a restricted free agent July 1, but Anaheim general manager Bob Murray made sure his surprising find is bound to the team through 2020-21.

The 24-year-old Despres quickly won a regular spot in Anaheim's lineup with physical two-way play, scoring six points in the Pacific Division champions' final 16 regular-season games.

Despres then stepped up in the playoffs, logging significant minutes as a top-four defenseman for a title contender. He scored seven points in the postseason while the Ducks fell one game short of the Stanley Cup finals.

"We've just touched the surface of his play," Ducks coach Bruce Boudreau said. "He's big and strong, and he's still growing into his body. He was a very good offensive defenseman [who] turned into a good defensive defenseman, and now if you can [combine] both of those things, I think you've got something special."

The 2009 first-round pick has six goals and 33 assists over four seasons in his career.

Simon Despres and the Ducks open their season Saturday at San Jose. Debora Robinson/Getty Images

Despres is a part of a tantalizing young core of talent on the blue line in Anaheim along with Hampus Lindholm, Sami Vatanen and Cam Fowler, Despres' normal defensive partner. Lindholm and Vatanen are scheduled to be restricted free agents next summer.

"It's a great team, great city, great fans, great environment to play hockey," Despres said. "I'm very pleased to play here a long time."

The three-time defending Pacific Division champions open the regular season at San Jose on Saturday night. Anaheim will be the last team in the NHL to play its season opener.

ESPN's Pierre LeBrun and The Associated Press contributed to this report.