Chelsea have agreed a deal in principle worth £12m, plus defender Marcus Alonso, for Barcelona striker Pierre-Emerick Aubameyang, according to Guillem Balague.
Aubameyang scored 13 goals in 24 appearances for Barca after joining the Spanish club from Arsenal in January.
He had a buyout clause of 100m euros (£83.4m) in his contract, but has only played eight minutes this season.
The 33-year-old would be Chelsea's seventh summer signing.
The Blues have brought in French defender Wesley Fofana for a fee in the region of £70m, England forward Raheem Sterling from Manchester City for £50m, Senegal defender Kalidou Koulibaly from Napoli for £34m, English midfielder Carney Chukwuemeka from Aston Villa for £20m, Spain left-back Marc Cucurella from Brighton for £60m and Italian midfielder Cesare Casadei from Inter Milan.
A deal for Aubameyang would mean Chelsea chairman Todd Boehly will have spent almost £250m in his first transfer window since buying the club from Roman Abramovich.