The Football Association is set to look into comments made about referee Howard Webb by Manchester United boss Sir Alex Ferguson, BBC Sport understands.
Ferguson was upset after the draw with Arsenal
Ferguson accused the official of being biased towards the Gunners during the 2-2 draw at the Emirates Stadium.
"He has a chance to be the top referee but it was a big game and, at times, he favoured Arsenal," Ferguson told MUTV.
"Their second goal came from him not giving a free-kick for a foul on Louis Saha. It should've been a foul for us."
However, Ferguson added that he believed it was difficult for referees not be influenced by hostile home crowds.
He has certainly got potential to be one of the best referees in the world
Former referee Dermot Gallagher on Howard Webb
"It is very hard for the referee," he stated. "On our bench, we were getting terrible abuse from people two or three feet away from us.
"There is a lack of security. It is absolutely disgraceful the abuse you and your staff take. All sorts of things are being shouted and screamed at you and there is an absolute danger here."
Former referee Dermot Gallagher said frustration may have led to Ferguson making his comments.
United were on the verge of victory before William Gallas salvaged a draw for Arsenal in injury time.
"Maybe some of his comments were born of disappointment. You are 93 minutes into the match, you think you've killed it off and then it goes against you," said Gallagher.
Gallagher also backed Webb to become one of football's best officials.
He said: "He has certainly got potential to be one of the best referees in the world.
"He is young, talented and has got great man-management skills. His recognition of offences on the field was first class and with any luck we could be seeing a future World Cup referee."