Crystal Palace have asked about Schalke centre back Ozan Kabak, who was on loan at Liverpool last season.
The 21-year old also has interest from Bundesliga clubs as financially stricken Schalke consider dropping their asking price.
Palace added Marc Guehi from Chelsea this week but have been monitoring developments with Turkey international Kabak for a couple of months.
Liverpool did not take up their option to sign Kabak as they had already decided to buy Ibrahima Konate from Red Bull Leipzig with talks initiated in December.