Fulham say they will take "the strongest possible action" after Aboubakar Kamara was racially abused on social media following his penalty miss against Huddersfield.
Claudio Ranieri said Kamara disobeyed team orders by seizing the ball and arguing with Aleksandar Mitrovic, who is the club's regular penalty taker, and subsequently missed the late spot kick.
Mitrovic netted in injury time to snap a six-game winless run for Fulham but the victory was marred by abusive posts on Kamara's social media accounts, some of which were racist.
A Fulham spokesperson said: "We are aware that numerous hurtful comments have been posted on Aboubakar Kamara's social media account.
"As a club that prides itself on our respect and civility, we condemn anyone associated with this repulsive activity.
"The club will provide all necessary support to Aboubakar and take the strongest possible action against those responsible."
Fulham boss Ranieri said Kamara disrespected him, the club, his team-mates and the crowd and is considering dropping him for Tuesday's game against Arsenal.
Mitrovic, however, was in a more forgiving mood.
"He's a striker, he's hungry for goals as well, maybe he wanted to score as well and he scored his last penalty," said Mitrovic.
"It's normal. He's young; these kind of things can happen. It's normal.
"You need to take care of each other. We had a bit of an argument but in the end he took the ball and I wished him luck and told him to stay focused and score. That's what he'd do as well.
"If he'd scored I'd have celebrated with him, like I scored. The most important thing is we got the three points and everything is behind us."