Barnsley have told their out-of-contract stars they will be offered new deals but are still wary of losing them.
The deals of captain Conor Hourihane, his midfield partner Josh Scowen and joint top-scorers Marley Watkins and Sam Winnall are all due to expire at the end of the current season.
Head coach Paul Heckingbottom said: "There have been initial approaches from the club to the players. But that will be ongoing. It's a case of us letting the players know we appreciate them and that we will be offering them new deals. Whether they sign it or not is another matter and that is the bit that can rumble on and on.
"Players can play themselves into a really strong position and we have to accept that we've succeeded off the back of the players doing really well. They have got the benefit of that now and they may want to see their contract out and see what happens in the summer. If the club can't tie them down then we might have to accept that."
Asked if the Reds would be willing to sell those players in January, rather than risk losing them for free in the summer, Heckingbottom said: "No.
"We want to stay in this league. We have made it clear that we don't need to sell. Our priority is being as strong as possible for this season and retaining our Championship status. We'd be silly to sell our better players unless we have a replacement in the squad.
"Going forward we need to know if someone is likely to stay in the summer or if they will definitely go, so we can start building in January. We have been planning for that since the summer."
