Barcelona have activated the option to secure the services of Marlon Santos from Fluminense on a permanent basis following his successful loan spell with the second team during the 2016-2017 campaign. The official confirmation comes days after reports in Spain claimed that Ernesto Valverde had identified the 21-year-old centre-back as a potential candidate to fill the gap left by Jeremy Mathieu's imminent departure.

The Brazilian defender joined Barca B during the last summer transfer window with hope he could break into the first-team in the long-term.

Marlon featured during pre-season with the senior team under Luis Enrique and in November was rewarded with his first-team debut in the Champions League's 2-0 victory at Celtic.

He made two further appearances under Enrique in the in the final two games of the La Liga season, being forced to start alongside Samuel Umtiti in the heart of the defence due to the absence of Javier Mascherano and Gerard Pique.

Meanwhile, the Brazilian has also made 24 appearances for the reserve side to help Gerard Lopez's side in their bid to earn a promotion to the second division of Spanish football. Marlon has been a key player for them and is expected to lead the defence in the two-legged play-off final which will take place against Racing Santander across the next two weekends.

Barcelona have therefore decided make his loan permanent in what is Valverde's first addition since being appointed as Enrique's successor.

"FC Barcelona have taken up the option to keep Marlon Santos at FC Barcelona for the next three seasons," a statement read..

Barcelona have not disclosed the details of the agreement but reports in Spain says that the total cost of the deal stands at around €6m (£5.3m, €6.7m). It is understood however that the Catalans will only pay €2m as Fluminense still owe them €4m from previous deals with youngsters such as Gerson and current Chelsea wing-back Kenedy.

The La Liga giants were expected to sign a new centre-back ahead of the new season with Frenchman Mathieu likely to leave the Nou Camp.

Mundo Deportivo reported last week that Valverde is ready to give Marlon a chance to cover the departure of the France centre-back and establish himself in the first team for the 2017-18 campaign