General manager Joe Nieuwendyk said Tuesday that the Stars will not re-sign Turco, a three-time All-Star who just completed his ninth season with the team.
"I just felt like it was time we went in a different direction," said Nieuwendyk, a former teammate of Turco's who became GM last summer. "I think he clearly understands the situation."
The 34-year-old Turco just completed a $22.8 million, four-year contract he signed in January 2006 that kept him from becoming a free agent at the end of that season.
Turco holds the Stars franchise record with 509 games played as a goaltender, winning 262 games with a .911 save percentage and a 2.31 goals-against average. He had 40 shutouts.
In 2002-03, his first as the starting goalie, he set a modern NHL record with a 1.72 GAA, a mark that has since been broken.
Turco was 21-26 in the playoffs for the Stars, including four shutouts. Three of those shutouts came in one series, in the first round of the 2007 playoffs against Vancouver when he had a .952 save percentage. The Stars were still knocked out in seven games.
"I want to thank Marty for 10 years of service here," Nieuwendyk said. "He's a friend, he's been a terrific competitor and a fan favorite. He has a lot to be proud of."
In 53 games this season, Turco posted a 22-20-11 record. He had a .913 save percentage and 2.72 GAA.
The 26-year-old Lehtonen, a native of Finland, was coming back from two back surgeries and had not played this season when acquired by the Stars. He appeared in 12 games for Dallas with a .911 save percentage and 2.81 GAA.
Lehtonen was the second overall pick by Atlanta in the 2002 draft.