Despite winning La Liga at a canter, Barcelona want to bolster their attacking options further to make themselves more competitive in the Champions League.
They have identified Willian as the solution to their problems as they plan to utilise his existing relationship with Philippe Coutinho, who plays alongside him for Brazil.
The Daily Mail reports that Willian's representatives have travelled to Barcelona for discussions. Chelsea are unwilling to sell but they are not in a strong bargaining position as they cannot offer Champions League football next season.
There is also continued uncertainty over the managerial position at Stamford Bridge, and Willian may take his chances with the more stable situation at Barcelona.
Manchester United have been strongly linked with the 29-year-old but despite registering their interest they are yet to post a concrete bid.
Willian is a very popular figure at Chelsea and he is contracted to the club for another two years, but with his 30th birthday less than two months away the Blues are aware that they are unlikely to get a better bid for an ageing player.
If Willian were to leave, Chelsea have a number of youthful options lined up to replace him including Dortmund's American winger Christian Pulisic and 22-year-old Russian World Cup star Aleksandr Gololvin, of CSKA Moscow.
Willian joined Chelsea from Anzhi Makhachkala in 2013 and has since made over 200 appearances for the Blues, scoring 44 goals and winning two Premier League titles.