Moriba has been linked with a transfer away from the Bundesliga side after an indifferent spell in Germany since arriving there in 2021.
The Guinean international was tipped for a big future at the Camp Nou after rising through the La Masia ranks from 2010 to 2019.
However, despite making his La Liga debut in 2021, a contractual dispute led to his exit less than six months later.
After struggling to make an impact, he was loaned to Los Che in January, with the Spanish giants bringing him back on loan at the start of 2022/23.
As per reports from Mundo Deportivo, Valencia are willing to make a €16m deal – plus €6m in variables – with a contract at the Estadio Mestalla until 2026.
If a deal can be wrapped up, Barcelona are due a 10% sell on clause, as part of their original deal with RB Leipzig.