Joe Hart is close to joining Celtic from Tottenham.
The former England and Manchester City goalkeeper, 34, has played 10 times since joining Spurs on a two-year deal last summer, but only in cup games.
Vasilis Barkas and Scott Bain have played in goal for Ange Postecoglou's side this season but neither has been able to keep a clean sheet.
Celtic face Czech hosts Jablonec in Thursday's Europa League third qualifying round first leg.
Keeper Pierluigi Gollini joined Tottenham from Atalanta this summer and the Londoners also have Alfie Whiteman as back-up to club captain Hugo Lloris.