Sky Sports understands a number of English clubs are tracking Nigerian midfielder Nosa Igiebor.
Bayer Leverkusen are confident that Hakan Calhanoglu will be a central figure at the club for many years.
Leeds manager Neil Warnock will not be relying purely on experienced campaigners to mount a promotion challenge next season.
The former Sheffield United and QPR boss has given himself just one season to steer Leeds back to the top flight, but insists his summer signings will represent good value for money.
Warnock said: "I talk to the chairman and all I can do is be realistic in the players that I want. I think the players I'm going to sign will not only be good value, but will be an investment for the club as well.
"They're not all going to be 37-year-olds giving me one year, they're going to be hungry players and I'm hoping I can make them into better players and that there will be some who are re-saleable.
"We'll be trying to get the blend of experience as well into that squad. When I've got one over the line we try and move that forward with [chief executive] Shaun Harvey and the chairman and try and come up with ways of doing that.
"At the same time I'm going to be doing my business on the other side, looking to thin the squad like I have done, not just releasing players, but lads transfer-listed and seeing what opportunities come to wheel and deal in that situation."