Premier League giants have been alerted after Sokratis Papastathopoulos pulled back from Borussia Dortmund contract talks.
Revier Sport says the Greece international has had a new contract on the table for several weeks, which would significantly improve his current salary.
However, the 29 year-old is now hesitating as interest from England arrives.
Sokratis is being linked with Manchester United and Arsenal this week, while Juventus are also keeping tabs on his situation.
And it's suggested should the defender push to leave, BVB chief Michael Zorc will demand €20m to sell.