The Spain international was registered as a first-team player by Barca in January, and it was announced he would wear the number six shirt.
Yet LaLiga sought to overturn a court decision that ruled in Barcelona's favour, with the league getting its way earlier in March, entitling it to reverse Gavi's registration.
Barcelona has been told it cannot register the 18-year-old's contract as it does not have room in its wage bill.
Gavi has subsequently been placed back on his youth contract, meaning he could leave Barca as a free agent at the end of the season.
A move away from Camp Nou for the teenager is unlikely. However, as it stands, Gavi will have to wear his old shirt number – 30 – for the remainder of the campaign.
After a breakthrough season in 2021-2022, Gavi has played 37 games for Barca this term, and his relegation in official status does not mean he cannot continue to play for Xavi's team.
