He would be a free transfer. The following is a google translate of the Spanish article, so some of the phrasing might seem clunky.
Gavi's reasons for considering signing for Chelsea
New contacts between the English club and the player's entourage are planned in the coming days to try to continue advancing. Barça is his first option, but…
Manu SainzManu_Sainz
Chelsea have taken the first step to sign Gavi, but it won't be the last. As AS announced this Tuesday, the English club met three weeks ago, in Madrid, with the player's agent, Iván De la Peña, to convey to him the desire to sign his representative. After that first contact in the capital of Spain, a second meeting that will have a greater depth is scheduled soon. The owners of the English club will be at that meeting, led by Todd Boehly, and it is expected that the soccer player's parents will also attend, accompanied by Iván de la Peña. The Chelsea owners want to convey to Gavi's parents the importance of the player in his ambitious project, as well as answer any questions they might have.The leak of the news given this Tuesday by AS about the start of contacts between Chelsea and Gavi's entourage has not changed the roadmap set by the English club to get the signing of the current Golden Boy and Kopa Award winner. The operation continues...
Gavi, for his part, is calm. He does not close doors, although his initial desire is to continue at the Camp Nou. For this reason, on September 15 , he renewed as a professional footballer with Barcelona until 2026. However, the bizarre contractual situation that he is experiencing and that is derived from the economic problems of the Barça club, is what has opened the way for Chelsea. And it is that if Barcelona does not manage to release 200 million of his salary limit before June 30 , his current professional contract would not be valid and he would be free, being able to sign for the blue team at zero cost. Chelsea, just in case, continues with his strategy. So,while Barcelona is unable to sign him up and he has had to see how he 'loses' the number '6' to put on the '30' again, the London team is willing to make him one of the highest paid players on the team, surpassing highly the salary signed in Barcelona.
In the strategy designed by Chelsea, not only the economic trick is played, but the signing of Luis Enrique for the next season is also being considered. The presence of the Asturian coach at Stamford Bridge would be one more incentive for the midfielder to take the step of leaving Barcelona and heading towards the Premier League. Not in vain, Luis Enrique is the coach who has bet the most on him, taking him to the National Team when he had still made very few merits in the First Division and in the face of widespread criticism from public opinion. Among the various controversial decisions made by Luis Enrique as head of the National Team, the commitment to Gavi was possibly the most successful. Both could meet again at Chelsea next season.
https://as.com/futbol/primera/las-razones-de-gavi-para-plantearse-fichar-por-el-Chelsea-n/?ssm=TW_CC