Lens chairman Gervais Martel has set a two-week deadline for Alou Diarra to decide his future.
The French international has been strongly linked with a move away from Stade Felix-Bollaert.
Roma and Galatasaray are both chasing the defensive midfielder with the player thought to be seriously considering leaving Lens.
Martel is keen for Diarra to make a decision on his future quickly so that the club know where they stand.
"We knew he could leave, because there was a clause in his contract," Martel told the club's official website.
"The club and Alou have always understood each other.
"The door is opened for him, but he could also stay if we don't agree the terms of a transfer quickly.
"It is normal for him to look for a bigger club, after having played the final of the World Cup.
"We have anticipated his departure, by investing a lot on promising Sidi Keita."