Bolton Wanderers manager Owen Coyle insists that players whose contracts end next summer have to earn new deals through their performances this season.
Coyle expressed his concern with the attitude of some of the Bolton players following his side's defeat 2-1 by Aston Villa at home in the Premier League last weekend.
It was the Trotters' 12th loss in the league this season and pushed them to the bottom of the table on just nine points from 15 matches.
A number of Trotters players will become free agents at the end of the 2011/12 campaign and Coyle says that all of them have to show professionalism even if they plan to leave the Reebok Stadium.
"We have 10 or 12 players out of contract next summer and I can totally understand why my owner would be reluctant to be handing out new contracts - until they are earned," said Coyle ahead of Saturday's trip to London to play Fulham.
"That in itself should be a huge incentive for those players, and it is two-fold.
"Either you want to be here at a fantastic club, or if you think the grass is greener on the other side, then you play your way into that situation where you will have different offers.
"By not performing, you are not doing yourself justice."
Star player and England international defender Gary Cahill's contract runs out in the summer and he is likely to attract a number of bids during the January transfer window.
But Coyle wants the 25-year-old to continue to give his best for Bolton, adding: "Of course, there is a contractual situation, and again, if there is business to be done, then so be it.
"If it means Gary goes with our blessing, then great, but what he has to do between now and January 1 is play to his maximum.
"If he does, there is no doubt there will be top clubs clamouring for Gary."