After vocal encouragement for his return from the crowd and teammates at Pittsburgh's Stanley Cup parade on June 15, as well as expressing his own affection for the city and team, Guerin signed a one-year contract extension with the Penguins on June 29 at a greatly reduced salary to play through the 2009–10 season. He became the first player to have a 20-goal season with seven different teams and one of only three to have a 20-goal season with five or more different teams (the two others being Eddie Shack and Ray Sheppard). Ray Shero, the general manager for the Penguins opted not to offer Guerin a contract for the 2010–11 season. On September 7, 2010, the Philadelphia Flyers invited Guerin to try out at training camp, but on October 4, the Flyers released him prior to the start of the regular season.
On December 6, 2010, Guerin announced his retirement as a player from the NHL as a Pittsburgh Penguin. At the time of his retirement, Guerin ranked seventh all-time among Americans in the NHL with 429 goals.