Third baseman Ryan Zimmerman and the Washington Nationals agreed to a six-year, $100 million extension Sunday, baseball sources told ESPN The Magazine's Buster Olney. Zimmerman also received a full no-trade clause from the Nationals.

The Nationals announced Zimmerman's extension Sunday afternoon but didn't disclose financial terms.

The average annual value of Zimmerman's contract is $16.7 million, the most for any third baseman behind the New York Yankees' Alex Rodriguez ($27.5 million).

"It's nice that it's done," Zimmerman said at a news conference at the club's spring training stadium in Viera, Fla. "It's where I want to be. It's where I've always wanted to be."

Zimmerman's current contract was set to expire after the 2013 season. The extension includes a seventh-year option that could keep Zimmerman in a Nationals uniform through the 2020 season. Zimmerman, who is due to earn $26 million over the next two seasons of his current contract, could potentially earn $150 million if the 2020 option is picked up, the sources said.

Zimmerman is one of six major leaguers signed through at least 2019, joining Albert Pujols of the Angels, Prince Fielder of the Tigers, Troy Tulowitzki of the Rockies, Ryan Braun of the Brewers and Matt Kemp of the Dodgers.

"I love pressure. I don't think people get these kinds of contracts that don't want to be in pressure situations. Ever since I've been here, I've wanted to be the guy that's up last in the ninth inning," Zimmerman said. "I've wanted to be the guy that everyone looks to. I've wanted to be the so-called leader. I relish being that guy. I love it. I wouldn't have it any other way."

Zimmerman's contract was negotiated by his agent, Brodie Van Wagenen of CAA Sports.

The two sides talked late into Saturday night, making enough progress for Zimmerman to extend a Saturday deadline that coincided with the start of full-squad workouts. The 27-year-old wanted to get a deal done or shelve the talks so his contract situation wouldn't be a distraction to the team, which has high hopes in the NL East this season.