Ryan Callahan may be forced to retire from NHL due to injury
Ryan Callahan Diagnosed with Degenerative Back Disease
Ryan Callahan retires from NHL with degenerative back disease
NHL's All-Appendectomy Team - Sports Illustrated
Former Lightning forward Ryan Callahan moves into new role
Ryan Callahan may be forced to retire from NHL due to injury
Rangers: Newly Retired Stepan Remembered as Beloved Blueshirt
Ryan Callahan announces retirement after 13 NHL seasons
Martin St. Louis to become first Lightning player to have number retired
What Ryan Callahan's career-ending injury means for the Lightning offseason - The Athletic