Oldham's Sean Eardley has been forced to quit playing because of a heart condition.
The 19-year-old, who was still to make his first team debut, has been advised by doctors to retire.
Eardley admitted he was extremely disappointed to be forced to hang up his boots.
"I have enjoyed my time at the club and am very disappointed it has ended this way," Eardley told the club's official website.
Meanwhile, Oldham have handed professional deals to six young players.
Michael Pearson, Matty Wolfenden, Terry Smith, Matty Barlow, Chris Lever and Chris Bagley have all been handed one-year deals.
One player who will not be staying a Boundary Park is Kelvin Lomax after he was informed his contract will not be renewed at the end of the season.