The two Premier League clubs are looking at a clip of the two players at a New Year’s Eve party, something which broke the rules.
Mitrovic’s partner recorded a video of the players celebrating with at least seven other people at the gathering with different households mixing.
Fulham have already had their last two games called off due to Covid cases, the latest one being against Burnley.
Luka Milivojevic has issued the statement: “I want to publicly apologise for my actions on New Year’s Eve. As captain of Crystal Palace Football Club I am fully aware that my responsibilities go beyond football, and that in this instance, I have let the fans, the club, my manager and teammates down.
“In what is a really difficult and challenging moment for everyone, I am truly grateful that I am able to continue to do the job I love and I do not take this for granted. I am very sorry to anyone who has been made to feel angry, hurt or upset by my actions.
“I am making a donation to the local NHS service to help them continue their incredible work in our community fighting this virus.”
Government rules state that people living in a Tier 4 area ‘must not meet socially indoors with family or friends unless they are part of your household or support bubble.’
In another video published to Instagram, Mitrovic is seen playing football with Milivojevic and another man as well as two children.
Janjic subsequently deleted her Instagram account, with Milivojevic’s wife Milica having been tagged in the posts.
Milivojevic’s Palace, meanwhile, were in action on Saturday afternoon when they beat Sheffield United.
Fulham posted a statement, which read: ‘Following further new positive results returned from the most recent Covid-19 tests, the Club can confirm that this Sunday’s away fixture at Burnley has been postponed after discussions with the Premier League and advice from medical teams.
‘Those who tested positive are self-isolating in line with UK Government and Premier League guidance.
‘The welfare of our players, staff and their families continue to be of paramount importance, and we wish those who have tested positive a safe and speedy recovery.’
Milivojevic was named captain for the game that weekend, something the Crystal Palace boss defended.
“In that respect we weren’t concerned about breaching any Premier League protocols and therefore I think it was correct Luka played the game,” Roy said.
“It was a question of him in his household having his fellow Serb Mitrovic round to join them, so that is a clear breach of coronavirus rules.
“We condemn it, we certainly apologise for it and I am sure Luka will as well. As far as I am concerned he must take full responsibility for that.
“It is an internal matter that we will deal with but as far as I am concerned there is nothing positive I can say on the matter.”
Fans reacted as Milivojevic speaks out on THAT concerning footage of him and Mitrovic…
@gazbod: Tepid. An underestimation of how angry, in the current lockdown atmosphere, supporters are.
@mycpfc: what more can he do than that? not sure what you were expecting other than an apology.
@D_Bennett: People acting like half the population haven’t broken the rules in the last ten months. He has apologised now time to move on.
@PrinceAyew1: Unbelievable, complete disregard of what the public is going through
@StephFuller_: If the captaincy hasn’t been removed ,then it should be.
@Sitdown_Jim: But is he still captain? If he is it’s unacceptable
@palacesam: luka has to go blud
@Troomp: Late apology. Where’s the club’s statement? Doesn’t feel enough.
@O11yC: Not enough, frankly. An underwhelming statement. And where is the sanction from the club? Doesn’t need to be hung out to dry, but should be more than just having to write that he’s sorry.
@MarkDre44138040: I wish I earned what he does he thinks he is above the law look at what the rest of us have to suffer no seeing family and loosing jobs
@nickgusset: Disgusting pathetic apology. I’m gonna boycott attending home games for a bit.
@DrizzyCPFC: Justice for Cardo, captain him instead
@Leedsfan247: Anyone else who behaved like this would not be able to continue in the job they love. Never mind, just throw a few of the excessive notes I am paid every week and the problem will go away!
@alex_westry: He shouldn’t have done what he did and I don’t think that he should be captain of our club doing that. At least he’s donating to NHS but it still doesn’t excuse his actions.
@victoriaokeefe: Not good enough.
@tgh316: I have nothing against Luka but he should be stripped of captaincy and placed on the bench for this, apology or not.
@CiaranCPFC: Don’t care, why is he our captain.
@b3n_br4dy: Still should be stripped of the captaincy