Chelsea will block any attempts by Jose Mourinho to sign Willian, Standard Sport understands.
Manchester United have been linked with a £60m bid for the Brazil international, who was voted by Chelsea fans as their Player of the Year this term.
The 27-year-old has two years left on his contract and Chelsea have yet to agree an extension.
Willian was signed by Mourinho for £30m from Anzhi Makhachkala in 2013 and thrived under him at Stamford Bridge.
But Chelsea are determined to keep their prize asset and plan to resist attempts by Mourinho to sign any of his former players.
Chelsea have also been boosted by the news that Romelu Lukaku has confirmed he will leave Everton this summer.
The Blues are keen to buy back the striker, who has made a return to west London his first choice destination.
Lukaku said: "I'm at a point where I have to make a good career choice. I have had a very good season, but it is time for me to write myself a CV. I got that trophy-winning mindset from Chelsea."
