Crystal Palace are willing to let Max Meyer go during the January transfer window.
The midfielder has only made one appearance so far this season - in the Carabao Cup defeat by Bournemouth - and now has less than six months left on a huge deal worth £170,000 a week with fees and bonuses included.
Bundesliga strugglers Cologne, who are battling against relegation with just 11 points from 14 games, have shown an interest in signing the 25-year-old this month.
Palace appeared to have pulled off a coup when they signed the highly-rated Meyer on a free transfer in 2018, paying just £450,000 in compensation to Schalke.