St Johnstone defender David McCracken will face about six weeks on the sidelines after it was confirmed he has sustained a fractured cheekbone.
The 31-year old centre-half suffered the injury in an aerial challenge with Victor Wanyama in Sunday's 1-1 draw at Parkhead and may yet require surgery.
"The centre-half fractured a cheek bone in a clash of heads with Victor Wanyama after only five minutes of Sunday's clash with Celtic and although further diagnosis will take place later today, the medical opinion at this stage is that it is fractured in several places and surgery cannot be ruled out," read a club statement.
