Chelsea have reached an agreement with Atletico Madrid to sign midfielder Saul Niguez.
The Spaniard has been heavily linked with the Blues this summer, and the club have eventually sealed the deal.
They have agreed to pay a €4m loan fee up front with the option to buy for around €35m at the end of the season.
Niguez is unlikely to travel to the English capital. The medical tests are expected to be conducted in Madrid.
Despite the short timescale, there is confidence from all parties that the transfer will be completed in time.
The Blues are not expected to conduct any more transfer business before the transfer window shuts at 11.00pm.
They were keen on signing Sevilla’s Jules Kounde, but a deal is off as they are reluctant to pay the €80m release clause.
The Blues have refused to pay more than €50m for the Frenchman. Sevilla won’t negotiate for the player on deadline day.