At the end of the 2005–06 season, when starting Maple Leafs goaltender Ed Belfour was injured, Tellqvist played in two consecutive games against the Montreal Canadiens when the Leafs were struggling to make the playoffs near the end of the season.

On March 12, 2007, in a game against the Philadelphia Flyers, he stopped all 24 shots to record his fourth career NHL shutout.

For the 2007–08 season, Tellqvist competed for Phoenix's starting goaltender position with Alex Auld and David Aebischer.

On March 4, 2009, Tellqvist was traded by the Coyotes to the Buffalo Sabres in exchange for a fourth-round draft pick in 2010.

On May 1, 2009, Tellqvist signed with Ak Bars Kazan of the Kontinental Hockey League (KHL) for the 2009–10 season.