Uefa have confirmed they will investigate the incident where Morten Gamst Pedersen was hit with beer during Blackburn's goalless draw with Feyenoord on Thursday.
Pedersen was soaked in beer after a cup was thrown at him from Feyenoord fans as he went to take a throw-in the 13th minute at De Kuip.
The Norwegian international and Rovers boss Mark Hughes played down the incident after the game, but Uefa have revealed they will look into the matter.
A Uefa spokesman said: "The matter was mentioned by the Uefa match delegate and a case has been opened. It will be investigated and is likely to be dealt with by the control and disciplinary panel on December 7."
If found guilty Feyenoord could find themselves in trouble with Uefa.