Primeau was acquired by the San Jose Sharks from the Penguins in exchange for Matt Bradley on March 11, 2003.

After a career year in 2003–04, Primeau was eligible for group IV unrestricted free agency.

Primeau was traded to the Boston Bruins on November 30, 2005, (along with Brad Stuart and Marco Sturm) in exchange for Joe Thornton.

In February 2007, the Bruins traded him to the Calgary Flames (again along with Brad Stuart) in exchange for Chuck Kobasew and Andrew Ference.

On July 27, 2009, Primeau was traded to the Toronto Maple Leafs (along with a second round pick in the 2011 NHL Entry Draft) in exchange for forward Colin Stuart, defenceman Anton Strålman and a seventh-round pick in 2012.