Swans boss Brendan Rodgers told the South Wales Evening Post: "From next year, if people are going into the last year of their contracts and they are not going to sign, then as a football club we need to try to earn what we can. I think that's what you have to do from a business perspective.
"Thankfully, I have no worries about the attitude of any of the players who are in their last year now. But it's a situation I would prefer not to have.
"I think we missed the chance in the summer to maximise the capacity to bring money in. From the club's perspective and the player's perspective, you will not get so much from doing something in January."