On February 2, 2007, Guerin became the 214th NHL player to play in 1,000 games. Later that month, he was traded to the San Jose Sharks in exchange for Ville Nieminen, prospect Jay Barriball and a conditional first-round pick (either New Jersey's in 2007 or San Jose's in 2008). During the subsequent off-season, Guerin signed a two-year contract with the New York Islanders. On July 9, 2007, he was named captain of the Islanders, making him the 11th captain in team history.