Carlisle, chairman of the PFA, revealed he has already had several meetings with Reading striker Roberts, who, along with Ferdinand, refused to wear a Kick It Out T-shirt last weekend. However, the nature of the proposals surrounding the potential breakaway group, which could sever links with the PFA, are still unknown by the union.
"I've had a number of conversations with Jason over the past few months. The most recent of them was on Sunday and they will continue," Clarke said. "Jason explained one or two things to me but I don't know what the full intentions or the requests are of this breakaway group."
He added: "Until we get everyone in and fully ascertain what they want and the direction they want to go in I can't really comment much further. The threat is very real because the proposal is there and the discussions have been had so it's obviously something that has been mooted within the industry.
"We have been having meetings with Jason and we have desperately been trying to get Rio into the meetings and that will continue.
"We will have those discussions with them at the time. We need to know exactly what it is they are wanting. Whether this is a movement that is in full flow and whether they think it is going to happen irrespectively, or whether it is something where they are trying to instigate change within the organisations that are currently in place.
"These are things that we have to hear, assess and weigh up."
Clarke is concerned the potential formation of a separate players' union could derail current efforts to drive racism out of football.
Manchester United defender Ferdinand was one of the players who did not wear a Kick it Out campaign T-shirt in the warm-up to United's match against Stoke City at Old Trafford at the weekend. Carlisle backed Ferdinand's right to free speech after his protest but is cautious about the benefits a breakaway group would bring in the fight against racism.
"It has the potential to be divisive as when you establish a black players union it would instantly define 'us and them' and that's something we really need to work against," Carlisle said. "We don't need to separate the players when the whole focus and goal of anti-racism is to campaign for unity so that is something we will be talking about, definitely."
Source: PA
Source: PA