Leighton, who helped lead Philadelphia to the Stanley Cup Finals last June, underwent offseason knee surgery and had only played in one game this season, a 7-4 win over the Kings in Los Angeles last week.
Philadelphia was in a rare spot, with three healthy, NHL-ready goaltenders on the roster. Leighton's departure means the Flyers will go with Brian Boucher and Sergei Bobrovsky the rest of the way.
Fan, follow and download: Get the latest from NBCPhiladelphia.com anytime, anywhere. Follow us on Twitter, Facebook and NBC Philadelphia. Sign up for our sports newsletter. And, get breaking news delivered right to your mobile phone -- just text PHIBREAKING to 639710 to sign up. (Message and data rates may apply.)