The PSG forward only made a world-record €222 million switch to the French capital in the summer but has been continuously linked with a move to Barca's fierce La Liga rivals.
Goal understands that PSG would have been willing to discuss a potential transfer had they been crowned European champions in 2017-18 but their Champions League last-16 exit means any willingness to enter into negotiations seems highly unlikely.
Publicly the Ligue 1 club have stated that they have no plans to sell their prized asset, who has scored 28 goals in 30 games this season before he suffered a fractured metatarsal on February 25 against Marseille.
The Madrid rumours will refuse to go away as summer approaches, however, and Umtiti, who played with Neymar at Barca, believes the transfer will take place if both Madrid and his former Brazilian team-mate want it to.
He told Canal+: "In football, anything is possible. Just because you played for Barca that doesn't mean you can't go to Real. If he wants to go, and Real wants him, it will be done."
Neymar missed the second leg of PSG's Champions League defeat to Real Madrid and also Saturday's Coupe de la Ligue triumph over Monaco.
He has, however, been tipped to make a return to Paris in the next "two or three weeks" by head coach Unai Emery, going some way to allay fears that he could miss the end-of-season run-in and then the World Cup in Russia.