Chelsea are reportedly considering a swap deal that would bring Paris Saint-Germain attacker Javier Pastore to Stamford Bridge and see Diego Costa move the other way.
The Blues have previously been credited with an interest in 27-year-old Pastore and were said to be considering a bid in the January transfer window, but an offer failed to materialise.
The Argentine has been at the Parc des Princes since 2011 but has found game time hard to come by under Unai Emery this season, making just 15 appearances in all competitions.
According to Tuttomercatoweb, the Premier League leaders have been made aware of PSG's interest in Costa, who had a training ground bust-up with manager Antonio Conte earlier this season, and are mulling over whether to do a straight swap for Pastore.
Asked about switching to the French league recently, Costa responded "why not?" and referred to PSG as a "respected" club.