Chelsea are confident that Sevilla's Jules Kounde will end up at Stamford Bridge this summer but their approach is conditional on Kurt Zouma moving to West Ham.
With the Blues having found a verbal agreement to sign the 22-year-old, they also know the terms that the Liga side will agree on.
Meanwhile, Zouma is completing a medical in Paris and is finalising the finer details on personal terms of a five-year contract with the Hammers.
What will Kounde cost?
Reports have suggested Kounde will cost £42m ($58m) plus bonuses, but sources close to Goal expect the fee will be higher.
The France international has a €90m (£77m/$106m) release clause, but Chelsea are expected to be able to negotiate a cheaper fee of around €60-€65m (£51m/$56m).
What are people saying about Kounde?
Sevilla have finally acknowledged that they have spoken to a club, thought to be Chelsea, about selling Kounde.
“It is true that there was an offer for Kounde that we turned down,” club president Jose Castro explained to reporters on Wednesday.
“Right now there is no concrete offer for the player. If it comes, we will look at it as we always have done. If we have to [sell], we will do, as long as those resources can be re-invested in the club to keep improving and expand our trophy cabinet.
“While the market is open, anything can happen. We have players who could leave. Anything can happen this time of year until the 31st. It is a window where there have been few moves in most clubs, but not in ours.”
Privately, Thomas Tuchel is known to have mentioned Kounde's name when reassuring other players in his defence about their roles.
This comes amid contract talks over new deals for centre-backs Andreas Christensen, Antonio Rudiger and Trevoh Chalobah.
It is expected that Christensen will sign but the talks could go beyond the transfer window despite him having less than 12 months left on his current deal.
In Rudiger's case, there are fears that he will wind down his contract to field offers in January over a free transfer, given his next deal will be the last big one of his career.
Chalobah is largely expected to sign a new five-year deal after breaking into Tuchel's first-team, despite Kounde's likely arrival.