Manager Philippe Clement says he cannot force players to leave Rangers even if they have been told they are no longer part of his first-team plans.
Todd Cantwell informed Clement in pre-season that he wished to leave Ibrox, while fellow attacking midfielder Ianis Hagi has been told to find a new club.
Winger Rabbi Matondo has been linked move to Leeds United, but Clement would not comment on media reports.
The manager knows Rangers must lower the wage bill before adding to the squad, but admitted he is limited in his power.
“It’s important for the club to sell players to also get players,” Clement said.
“That is the case and some of them have known that a really long time and they are still in the building, so that makes things more difficult, but it is what it is.
“I cannot put a gun on their heads to get them out the building, that is not the idea.
“It’s not something I can control. All the energy is on the players who are here, the players that will be here and to get the next result.”
Clement went on to reveal Ridvan Yilmaz is facing up to six weeks out as Rangers prepare for the Premier Sports Cup last-16 tie against St Johnstone on Saturday.
The left-back was carried off on a stretcher in Tuesday’s 2-0 Champions League qualifying defeat by Dynamo Kyiv with what looked like a thigh injury.
“I don’t like to say too much in detail but it will be around four to six weeks, something like that,” said Clement, who is also without Nicolas Raskin and Oscar Cortes, while Scott Wright and Leon Balogun are weekend doubts.
“I don’t think we have the assets to (bring in another left-back), we have to put all the focus on the positions we need for the squad for the rest of the season.
“Bringing in another full-back now and to have Ridvan and have Jefte – and we have a third one with Robbie Fraser who has made a good evolution in the last couple of months.”