banned for throwing a missile
Rangers say a lifetime ban from Ibrox is the likely punishment for the fan who threw a paper cup at Celtic goalscorer Stilian Petrov on Sunday.
The club are currently examining CCTV footage of the incident in an attempt to identify the culprit.
A Rangers spokeswoman added: "The club condemns this type of behaviour."
The Scottish Football Association will also look into the matter, which is certain to be included in the match report of referee Stuart Dougal.
"If the incident is mentioned in the referee's report, then it would go before the disciplinary committee," said the SFA's head of discipline Drew Herbertson.
Petrov was struck by the cup as he celebrated his opening goal in the 2-1 win over Rangers.
He left the field to receive treatment, after being booked for over-celebrating, before returning.
Missile-throwing incidents have become a worrying trend in the Scottish Premier League this season, with Celtic and Hearts both being subject to Scottish Football Association discussions.
Rangers midfielder Fernando Ricksen was hit by a cigarette lighter thrown from among Celtic fans as he prepared to take a corner in the last Old Firm derby.
Objects were thrown on to the pitch by Hearts fans during a stormy SPL encounter between Hearts and Rangers at Tynecastle last month.
The SFA took no action on those occasions but wrote to all SPL clubs warning that sanctions could be taken if incidents continued.
Referee John Rowbotham was struck by a coin thrown during this month's Edinburgh derby at Tynecastle.
