Chesterfield goalkeeper Tommy Lee will be out for between six to eight weeks with the shoulder injury he suffered against Oldham in midweek.
Lee has damaged ligaments but the 26-year-old has been told by a specialist that he will not require surgery.
Lee landed awkwardly after coming to collect a cross during the closing stages of Chesterfield's 2-1 home victory over Oldham in the Johnstone's Paint Trophy on Tuesday night.
Reacting to the news, caretaker manager Tommy Wright said: "Obviously it's a blow to lose Tommy but the positive news is that he doesn't need surgery; it could have been a lot worse.
"We've sent him to a top specialist, somebody who looks after the British Lions rugby team, so he's in good hands. He's a hard worker and the specialist is confident he can make a full recovery within six to eight weeks."
Lee suffered a groin injury in September last year that kept him sidelined for almost three months, during which time the Spireites lost eight of their 11 league matches.