The Football Association is looking into comments attributed to Chelsea's Ashley Cole about referee Graham Poll in the Blues' defeat at Tottenham.
Poll and Cole clash at White Hart Lane
Poll booked six Chelsea players, sent off John Terry and disallowed a Didier Drogba goal during Sunday's match.
"We are communicating with the match officials, Chelsea, Ashley Cole and Frank Lampard," said an FA spokesman.
Chelsea have confirmed that boss Jose Mourinho and referees' chief Keith Hackett have made contact since Sunday.
Hackett, head of the Professional Game Match Officials Board, has said he would be willing to meet with Mourinho to discuss any refereeing issues the Portuguese coach might have.
I am happy to hear Mr Hackett is prepared to meet and I will meet with him when he wants
Chelsea boss Jose Mourinho
A Chelsea statement read: "We can confirm that Mourinho and Hackett have been in touch.
"Mourinho sent him a private email on Monday in which he stressed his respect for the Hackett, who he has met before.
"Although the exact contents of this email will remain private, in general terms it addressed some refereeing issues which have arisen this season."
Mourinho added: "I am happy to hear Mr Hackett is prepared to meet and I will meet with him when he wants.
"I have confidence that he is a football man and he respects the views of other football people."
Left-back Cole was one of the Chelsea players who was yellow-carded and he was quoted as saying: "With my booking, I said to him, 'I'm more than 10 yards. Why should I go back if I am more than 10 yards?'
"And he said, 'Because I said so.' I said, 'But I'm more than 10 yards', and that was it. Yellow card. No warning or explanation.
"I'm not moaning, I'm really not, but we shouldn't lose a game like that.
"Once again we scored a goal that was fine. I've seen it on TV and the referee has robbed us because if we had gone to 2-0 then the game would have been dead."
Cole was quoted as saying that he believed that Chelsea, like his previous club Arsenal, are now being singled out by referees because of their success.
He added: "When I was at Arsenal and we started to win things, the referees started to question our discipline and give us yellow cards. I have come to Chelsea and it's exactly the same.
"It's definitely to do with the team that's winning most. Chelsea are not a dirty team. It's crazy. We have to stick together, put this game behind us, look forward to the next one and win it."
Hackett says he will investigate Chelsea's claims that official Poll said they "needed to be taught a lesson" at Tottenham.
It puts doubt in the public's mind about the integrity of one of my referees but it will be investigated
Newspaper reports alleged Poll made the remarks and suggested he told Chelsea: "Your discipline is out of order".
Hackett told BBC Five Live: "I have very serious doubts that one of our most experienced and world-class refs would make that kind of comment."
"It is disappointing. It puts doubt in the public's mind about the integrity of one of my referees but it will be investigated."
Hackett also revealed that all the officials were on open microphones - and his initial inquiries led him to believe Poll had not made the comments.
He added: "The player who has made the comments should be aware that the referee, along with his assistant referees, were all wearing microphones.
"My assessor can hear from before kick-off to the end what is being said. If anything untoward was said I will be able to discuss it with Graham's colleagues on the day.
"Already having spoken to one of his colleagues, who was listening, it has been flatly denied."
Hackett has told Poll not to make a public comment about the match while the matter is being investigated.
Terry also added to the controversy by claiming Poll gave him two differing reasons for his dismissal.
He said: "On the pitch, Graham Poll said to me the second yellow card was for the barge on Hossam Ghaly where I kept running.
"After the game he said it was for the fall when Ledley King and I fell. I am just really disappointed that it is my first time sent-off for Chelsea."