Barcelona centre-back Marlon Santos has completed a loan move to OGC Nice for the next two campaigns - only two months after the La Liga giants activated an option to secure his services from Fluminense on a permanent basis.
The La Liga giants retain an option of recalling him after the end of the first season with reports in Spain adding that Nice also have an option to buy him permanently for around €20m (£18.5m).
Marlon was recruited on loan by Barcelona B last summer as a prospect.
The Brazilian star played an important role in seeing Gerard Lopez's side promoted to the second tier of Spanish football and also made three appearances for the first-team under Luis Enrique, starting the final two games of the La Liga season due to the absence of Javier Mascherano and Gerard Pique.
On 15 June, Barcelona activated an option to make his loan from Fluminense permanent and promoted him to the first-team.
The Brazilian made the pre-season under Valverde and was expected to fill the gap left by the release of Jeremy Mathieu this season.
However, the Barcelona boss suggested last week that Marlon may instead need to move on loan somewhere else to continue his development before having a chance to establish himself in the firs-team.
"We have five centre-backs. He is young and he may leave. We have to assess the situation and talk with him. We will see [whether he leaves] in the next few days," Valverde said.
Barcelona have thus agreed to send him to Nice for the next two campaigns despite the Catalans' recent unsuccessful negotiations with the Ligue 1 side over Jean Michael Seri.
"FC Barcelona and OGC Nice have reached an agreement for the loan transfer of Marlon Santos, 21, for the next two seasons. An option for the Club to take the player back after the first season is also in place," the club confirmed through an official statement.
The clubs have not disclosed the financial details of the agreement but Mundo Deportivo says that the deal also includes an option for Nice to make the deal permanent for around €20m (£15m).
Marlon's departure could give Thomas Vermalen a chance to serve as Barcelona's fourth choice centre-back this season even though the former Arsenal defender had been widely tipped to leave the Nou Camp following his struggling loan spell at AS Roma.
Yet, Valverde currently only has three players in Gerard Pique, Samuel Umtiti and Javier Mascherano to cover the position.
Marlon is the sixth player to leave Barcelona during the current transfer window following the previous departures of Sergi Samper, Neymar, Cristian Tello, Mathieu and goalkeeper Jordi Masip.
Samper was also sent on loan to UD Las Palmas last week, while earlier in the summer Neymar and Cristian Tello also left the club to join Paris Saint-Germain and Real Betis in deals worth €222m (£171m) and €4m (£3.1m). Meanwhile, Mathieu and goalkeeper Masip were released after the termination of their contracts.