Chelsea have started to sell as they prepare for a spending spree on Tiemoue Bakayoko and Alex Sandro and are inserting buy-back clauses into the deals for their departing young starlets.

Bertrand Traore completed a switch to Lyon worth up to £16million on Monday, with Chelsea due 15 per cent of any profit the French club make on the fee should they sell him down the line.

Chelsea have also inserted a buy-back option, while similar clauses will be discussed in Bournemouth’s £20m move for defender Nathan Ake.

Nathan Ake is on the move as Chelsea start to sell as they prepare for a spending spree

Bertrand Traore gives a thumbs-up after signing his five-year contract at new club Lyon

Chelsea sold Romelu Lukaku to Everton for £28m but didn't insert a buy-back clause in the deal

The absence of such a clause when Romelu Lukaku was sold has returned to haunt the London club who want to re-sign the centre-forward.

Everton have told Chelsea that Lukaku will cost them a world-record fee of £100m.

The Premier League champions have found prices are soaring with Monaco midfielder Bakayoko is set to become their first signing of the summer if they can complete the final details of a transfer worth £35m.

Nemanja Matic, who is moving closer to a £40m switch to Manchester United, will make way for Bakayoko in Antonio Conte’s first team squad.

Chelsea are expected to complete the signing of midfielder Tiemoue Bakayoko this week

Chelsea's £61million move for Alex Sandro will make him the most expensive defender ever

Ake’s proposed move to Bournemouth will clear space for Sandro, the Brazilian left-back who will cost £61m from Juventus.

The versatile Dutch defender impressed Eddie Howe when he spent the first half of last season on loan with the Cherries until he was recalled in January as cover.

Ake performed brilliantly when he deputised for Gary Cahill in the FA Cup semi-final but his chances were limited and the 22-year-old is determined to find regular football.

Defender Ake spent last season on loan at Bournemouth before being recalled by Chelsea

Southampton showed an interest in Ake as a potential replacement for Virgil van Dijk, whose proposed move away from St Mary’s stalled when Liverpool were accused of an illegal approach.

Chelsea will test their resolve again now Saints have replaced manager Claude Puel with Mauricio Pellegrino but Bournemouth have seized the initiative in the chase for Ake.

Sandro wants to leave for Chelsea and Juventus will not stand in his way but they will demand £61 for the 26-year-old left-back who cost £23m from Porto two years ago.