Uefa is to investigate an incident involving Blackburn's Morten Gamst Pedersen that occured during his side's encounter with Feyenoord on Thursday.
Pedersen helped his team to a goalless draw in Holland
The Norwegian winger had a plastic cup containing beer thrown at him in the 13th minute when he went to take a throw-in during the Uefa Cup match.
"The matter was mentioned by the Uefa match delegate and a case has been opened," said a Uefa spokesperson.
"It will be investigated and is likely to be dealt with on 7 December."
However, Pedersen chose not to file a complaint following the incident.
"It's up to Uefa if they follow it up or not. I got beer in my face and had sticky eyes. It could have been worse but it should not happen," he said.
"But I am okay. There are no marks on me, just a bit of beer in my eyes."
He added: "Of course you think what might have happened if it was something else, like a hard thing, but it was just plastic."
Blackburn secured their passage into the knockout stages after picking up a point in a 0-0 draw in Rotterdam.