St Johnstone manager Tommy Wright remains in hospital after being admitted earlier this week.
The Saints boss complained of severe stomach pains on Monday and was told to seek advice at the Perth Royal Infirmary where he was spent the past few nights following his Tuesday arrival.
Wright will now undergo gall bladder surgery on Thursday as he puts side his preparation for the weekend's clash with Hibernian to concentrate on his health.
"Tommy was taken to hospital on Tuesday suffering from stomach pains and detained overnight for observation," Saints football administrator Paul Smith said.
"He will undergo surgery and the medical staff have been continuing to monitor him. Obviously, everyone at the club wishes him well and a speedy recovery."
