Aug 7 (Reuters) - Six-time Ballon d"Or winner Lionel Messi will hold a news conference on Sunday at Barcelona"s Camp Nou stadium following his surprise departure, the La Liga club said. Messi will speak at 1000 GMT after Barcelona said on Thursday the 34-year-old will leave the club, despite both parties having reached an agreement over a new contract, citing economic and structural obstacles to the renewal of the deal. Messi, who joined Barca"s youth set-up aged 13, is the club"s all-time top scorer and appearance maker with 672 goals in 778 games in all competitions. Barcelona president Joan Laporta said on Friday the club was forced to let star player Messi leave because his high wages coupled with strict La Liga financial rules could have jeopardised its future. read more Messi had wanted to sign a new contract at Barcelona on reduced terms, reportedly 50% below his current pay, but the club was unable to come up with an arrangement that also complied with the financial rules of La Liga. FREE AGENT MESSI Messi"s last contract, signed in 2017, was the most lucrative in world sport according to a January report in newspaper El Mundo. Forbes has listed him as the athlete with the world"s second-highest earnings in 2021, at $130 million. Messi, who helped Barcelona claim 10 league titles, four Champions Leagues and three Club World Cups, technically ended his 21-year association with the club at the end of June and is currently a free agent after his previous contract expired. French newspaper L"Equipe reported on Friday that Messi is set to join Paris St Germain, while the club"s manager Mauricio Pochettino also said the Argentine was an "option" that was being evaluated. read more Messi has also long been linked with a move to Manchester City, but manager Pep Guardiola said the Premier League champions had no plans to make a move for him. Some observers believe that the announcement of Messi"s departure is actually Barca boldly calling La Liga"s bluff over its financial rules. read more