Chelsea are reluctant to sell Cesc Fabregas due to his homegrown status.
The Daily Express says both the Premier League and UEFA require clubs to have eight home-grown players in their 25-man squad.
The 29-year-old is now one of six home-grown players in the squad at Stamford Bridge along with Asmir Begovic, Gary Cahill, John Terry, Victor Moses and Nathaniel Chalobah.
In fact, in order to avoid breaking the Premier League rules the Blues have had to leave blank spaces in their squad and will have to take advantage of the unlimited allowance of under-21 players if they hit a serious injury crisis.
And Cesc's departure would leave the Blues even shorter of eligible senior players.