The 19-year-old was the club’s joint top scorer last season as they struggled to a sixth-placed finish and is reportedly also attracting interest from the majority of Europe’s biggest clubs.
Lucas has already picked up 10 caps for Brazil, scoring one goal against Argentina last September.
The attacking midfielder was also named in Mano Menezes’ squad for 2011’s Copa America.
A release clause in Lucas’ contract is thought to be worth close to €88 million (£66.8m) but the Blues are unlikely to be willing to pay anywhere near that amount.
Chelsea seem keen to bolster their midfield and are apparently close to sealing a deal for Belgian youngster Kevin de Bruyne as well as having a bid turned down for Shakhtar’s Brazilian playmaker, Willian.