Dedryck Boyata is likely to be out of action for a further four weeks- missing both legs of the Europa League tie with Valencia.
The defender played the full 90 minutes of the Scottish Cup tie against Airdrie United/Clydebank on January 19 but then missed the midweek win over St Mirren four days later.
Brendan Rodgers had hoped to have Boyata available to face Hamilton on Saturday but a set-back to his abductor injury means that he is expected to miss the whole of February.
With Filip Benkovic ruled out for at least six weeks due to an ankle injury it means that Celtic will be without their first choice central defensive partnership for the critical February period.
Kris Ajer and Jozo Simunovic played together in the 2-0 win over St Johnstone on Wednesday night and will face the same opponents again on Sunday.
Yesterday Celtic turned down a number of bids to take Jack Hendry out on loan with the former Dundee defender now the back up should Ajer or Simunovic suffer any injuries.