"They are both quality coaches and men, but we have decided to go in a different direction with our coaching staff and we wish them well in their next endeavours," Nill said in a statement.
Gulutzan went 64-57-9 over two seasons with Dallas, who were in the mix for a playoff spot each year but fell just short of the goal.
The 41-year-old had previously guided the team's American Hockey League affiliate to the Calder Cup final in 2010.
Nill, after nearly two decades serving in various positions in Detroit's front office, took over earlier this month as general manager from Joe Nieuwendyk. The Hockey Hall of Famer Nieuwendyk served for four years as GM before being fired.
Dallas last made the playoffs in 2008, reaching the Western Conference final.
The Stars said they will retain former NHL player Curt Fraser as an assistant coach. Fraser spent 3 ½ season as head coach of the Atlanta Thrashers between 1999 and 2003.