Chelsea have reportedly considered using Filipe Luis as part of a deal to bring Atletico Madrid midfielder Koke to Stamford Bridge in the summer.
The Chelsea board are believed to be willing to give Jose Mourinho a big transfer fund in an attempt to improve their chances in next season's Champions League, and Koke has emerged as a possible target.
According to the Evening Standard, the Premier League leaders have not been put off by the 23-year-old's £48m release clause, and they are keen to make an approach when the transfer window reopens.
Luis left the Spanish capital for West London last summer, and recent reports have suggested that the La Liga champions are interested in re-signing him, which could be capitalised on in any talks.
Koke signed a new five-year deal with Atletico last May.