Lazio winger Loum Tchaouna was substituted after being racially abused by fans during his side’s Europa League win against Twente on Thursday.
Tchaouna, 21, was clearly incensed when he was taken off in the 89th minute of Lazio’s 2-0 win in the Netherlands.
The France Under-21 international appeared to imitate monkey noises when explaining to referee Nikola Dabanovic and the Lazio bench what had angered him.
Lazio manager Marco Baroni said he was preparing to substitute Spanish forward Pedro but decided to withdraw Tchaouna as he was clearly upset by the incident.
“The howling at Tchaouna? Unfortunately I confirm that the player perceived this,” Baroni told Sky Sport Italia.
“It’s a subject I don’t want to expand on now, we tried to calm him down and then I substituted him because he was no longer in the emotional condition to continue. But I think the fourth official saw what happened.”
BBC Sport has contacted Uefa for comment.
Uefa has already sanctioned several clubs for the racist behaviour of supporters in European competition this season.
Serie A club Lazio were fined £36,660 (45,000 euros) following incidents during their 4-1 Europa League win over Nice in Rome on 3 October, and will also have to close two sections of the Stadio Olimpico for their next Europa League home fixture.