The Spain international has been linked with a return to Atletico Madrid and, after missing out on Chelsea's defeat to Real Madrid on Saturday, may be set for the exit
Chelsea head coach Antonio Conte admitted he is unsure if striker Diego Costa will still be at the Premier League club when the transfer window closes.
Costa has been heavily linked with a return to Atletico Madrid, which has since signed Kevin Gameiro from Sevilla.
The 27-year-old Spain international's future remains uncertain after sitting out Saturday's 3-2 loss to Real Madrid in the International Champions Cup in Michigan.