Marlon Santos has completed his move from Barcelona to Nice on a two-year loan.
According to multiple reports, the Ligue 1 side also have an option to sign the 21-year-old -- who was given permission to miss Barca training on Tuesday to finalise the move -- at the end of the two years for €20 million.
Marlon joined Barca earlier this summer for €5m, having impressed on an initial one-year loan from Fluminense last year.
As well as helping Barca B earn promotion back to the second tier of Spanish football, he made three appearances for the first team, starting back-to-back games at the end of last season against Las Palmas and Eibar.
New Barca coach Ernesto Valverde included him on the club's tour of the United States in preseason but has since decided that the player's development will be best served playing regular football elsewhere.
With Marlon gone, Thomas Vermaelen is now expected to remain at the club for the time being unless a new centre-back is signed before the transfer window closes this week.
Sources told ESPN FC that Barca were keen to offload Vermaelen, but a move has failed to materialise and he now looks set to be Valverde's fourth-choice centre-back option.
Barca may yet decide to sign another central defender, though, and if not now then in January.
They considered a move for Real Sociedad's Inigo Martinez -- who has a buyout clause of €32m -- this summer and have an agreement with Palmeiras to sign Yerry Mina which runs until after next year's World Cup.