Sir Alex Ferguson has told MUTV that Rio Ferdinand let the club down after the defender failed to wear a Kick It Out T-shirt ahead of Manchester United's 4-2 victory over Stoke.
Reading striker Jason Roberts has been critical of the anti-racism campaign, telling BBC Sport it has not been "strong enough" and that John Terry's four-match ban for racially abusing Anton Ferdinand "is nowhere near harsh enough".
Ferguson had spoken out against Roberts' decision at his press conference on Friday, stressing his belief that he was "making the wrong point", and was adamant that that all of his players would wear the T-shirts. However, Ferdinand refused to comply.
"I am disappointed," Ferguson told MUTV. "I said yesterday that the players would be wearing it in support of the PFA and that every player should adhere to it, and he goes and lets us down. We will deal with it, don't worry."
However, Stoke boss Tony Pulis backed the right of players to decide whether or not they wanted to wear the Kick It Out shirts.
"They are given the opportunity and chance to decide,'' he said. "Let me say this about this country. People have the right to say yes or no. In a lot of countries you haven't the right.
"You can do what you want here. You have the chance to stand up and say you don't want to do it. This is a great country. It is multi-cultural. It is the best country in the world. They might have a gripe. Maybe rightly so, especially when you see incidents like the one in Serbia.
"I have never - and no club I have managed - have ever worried about anything like that. Black, white, Catholic, Protestant, you treat people as human beings. There is good and bad in religion and colour. You have to be straight down the middle and treat everyone the same.''
On the subject of funding for Kick It Out, he added: "I don't know enough about it. The black players at our football club get treated exactly the same as the white lads. There is no difference. That is the way it should be.''
Kick It Out chairman Lord Herman Ouseley had told ESPN beforehand that he did not believe it was wise for players to boycott the campaign and that wearing the T-shirts, shaking hands with opponents and showing respect represented the way forward.
Lord Ouseley said: "Would Rio tell England where to stick their shirt if picked or does he think the FA has done enough to tackle racism? Will he tell Manchester United where to stick their shirt and £150,000-a-week or have they done enough to tackle racism?"