The Stars announced on Friday that Lehtonen, 28, had signed a five-year, $29.5 million contract extension that will keep the goaltender with the team through the 2017-18 season.
Lehtonen, who has one season left on his current contract, would have been an unrestricted free agent following the 2012-13 season had he not signed.
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"It's been a great relationship since the day we acquired Kari," Stars general manager Joe Nieuwendyk said. "He's done everything we've asked of him. He's been very appreciative that we gave him another opportunity to get his career going. It's just a situation where it's a great fit for everybody."
When the Stars acquired Lehtonen from the Atlanta Thrashers on Feb. 9, 2010, he hadn't played in the 2009-10 season while recovering from back surgery. The past two seasons, however, have been his best -- he's won 66 games with seven shutouts.
"These guys gave me a chance," Lehtonen said of the Stars. "I said that again yesterday, thanks a lot again for giving me a chance to play. Things have worked out well. We're going the right direction and I think I can play better and better, that's why I wanted to stay here."
Despite missing time in 2011-12 with a groin injury, Lehtonen arguably had his best season. He set career bests with a 2.33 goals-against average and .922 save percentage, both of which ranked in the top 10 in the League, and his four shutouts tied a career best. He went 32-22-4 in 59 games.
The Stars added veterans Ray Whitney, Jaromir Jagr and Derek Roy during the offseason in a quest to get back to the Stanley Cup Playoffs for the first time since 2008, but Nieuwendyk believes it was imperative to have his top goaltender locked in for the immediate future.
"We've been talking to Kari and his agent for quite some time now and we felt this was important, to lock up Kari, for our franchise," Nieuwendyk said. "He was terrific through the process. We feel really good we have Kari locked up for the next five years."
Lehtonen said opting to stay in Dallas was an easy decision.
"We both wanted to do this and it was a fairly quick thing," he said.
"We've been talking to Kari and his agent for quite some time now and we felt this was important, to lock up Kari, for our franchise. He was terrific through the process. We feel really good we have Kari locked up for the next five years."
-- Dallas Stars GM Joe Nieuwendyk
The next step is getting to the playoffs. Lehtonen has been there once, starting two games for the Thrashers in their lone playoff appearance in 2007.
"It's always good to have things to look forward to and set as a goal," he said. "I'm sure we're going to get here and it's going to be a really exciting thing for a lot of guys. That's what playing for is all about, having success and winning games."
Nieuwendyk said having Lehtonen in place on a long-term deal also allows the club to take the maximum amount of time to develop its young goaltending prospects, among them Jack Campbell, the 11th pick of the 2010 NHL Draft, who will start his first professional season in 2012-13 with the club's American Hockey League affiliate, the Texas Stars.
"We don't have to rush any of these young goaltenders," Nieuwendyk said. "We have Cristopher Nilstorp in camp now who's showing some promise. I think we're well-stocked in the net now, but Kari is clearly our main guy right now. And that's a great thing. It gives Jack some time and other guys to season their games at the pro level, and we'll go from there."
Originally selected by the Thrashers with the second pick of the 2002 NHL Draft, Lehtonen has 166 wins in 334 games, with a 2.71 GAA and .914 save percentage.
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