Rio Ferdinand's decision to defy the wishes of Sir Alex Ferguson by refusing to wear a Kick It Out T-shirt during the warm-up to the Premier League meeting with Stoke City "embarrassed" the Manchester United manager, who has now hinted darkly that the defender may be punished for his stance.

Speaking to United's in-house TV channel, MUTV, after the 4-2 victory at Old Trafford Ferguson said: "I am disappointed. I said [on Friday] that the players would be wearing [the T-shirts] in support of the PFA [Professional Footballers' Association] and that every player should adhere to it. And he goes and lets us down. We will deal with it, don't worry."

Ferguson added: "I spoke to the press about it. It is embarrassing for me."

Ferguson had said his players would wear the shirts and condemned Jason Roberts, who also refused to wear a Kick It Out campaign T-shirt before Reading's defeat at Liverpool.

Reading's manager, Brian McDermott, backed Roberts's refusal to wear Kick it Out T-shirt, saying: "I spoke to Jason about it and he is very clear in his views. I support him 100%."

On Friday Ferguson criticised Roberts, the Reading striker, for his declaration that he would not wear the T-shirt because he feels let down by the campaign after the events of the past year, believing Kick It Out has not been strong enough. "I have to disagree with Jason Roberts, he is making the wrong point," Ferguson said. "Everyone should be united, all the players in the country wearing the warm-up tops. Yes, all my players will wear it. I think all the players will be wearing it. I only heard that Jason Roberts is different. He is very different, he plays his game and is in the studio 20 minutes after it, it's a great privilege."

Ferdinand was the sole United player not to wear the "One game, One community" T-shirt in the match-day squad, which included Patrice Evra, who was racially abused by Luis Suárez last season. Ferdinand eventually took his training top off to reveal he was wearing a United training shirt. It represented an obvious snub to the anti-racism campaign, and directly contradicted Ferguson's stance on the matter.

Ferdinand's brother, Anton, was racially abused by John Terry, for which the Chelsea captain received a four-match ban and a £220,000 fine from the Football Association. The club gave Terry their own record fine, but he remains the captain.

The Stoke manager, Tony Pulis, defended Ferdinand's right to make a personal stand: "Let me just say this about this country, they've got the right to say yes or no," he said.