Lionel Messi's exit from Barcelona is "irrevocable" according to prospective Camp Nou presidential candidate Toni Freixa, who expects the superstar forward to join Manchester City.

Messi shook world football last week by handing in his notice to leave Barcelona, who he joined as a 13-year-old.

The six-time Ballon d'Or winner's future could now become the subject of legal wrangling, with the Messi camp believing he is entitled to walk away from the final year of his Barca deal for free, while LaLiga issued a statement on Sunday to confirm its stance that the player's mammoth €700million release clause is still valid.

Messi did not show up for Barcelona's pre-season coronavirus testing on Sunday and failed to attend the first training session under newly installed head coach Ronald Koeman on Monday.

City are widely viewed as the frontrunners for Messi's signature and, once the considerable dust from the affair has settled, Freixa believes the 33-year-old will be reunited with his former coach Pep Guardiola at the Etihad Stadium.

"As I have heard from several sides, the decision in the player has matured over several years and is irrevocable. I don't believe that there is any going back," Freixa told Goal.

"I think a move to Man City is likely. With Pep, Messi experienced his most brilliant years in Barcelona.

"It would only be logical if both of them worked together again. City, like almost all English clubs, also has the financial means to build a team that can win anything.

"Messi is a player who strives for maximum success. He alone cannot achieve maximum success, he needs a team for that. He does not have one.

"Since the treble in 2015, [Champions League] success is missing. That is what concerns him. His decision is due to the negative sporting development in recent years."

Freixa told Radio Marca last week he was "disappointed" by Messi's unilateral move to end his Barcelona career, claiming it was made "without respecting" the club.

However, he believes incumbent president Josep Maria Bartomeu must take a hefty share of the blame for a situation he views as "a disaster".

"The president is the main person in charge and primarily measured by the team's successes on the pitch. If these fail to materialize and an important figure such as Messi then thinks he can be more successful elsewhere, this naturally falls back on the main person responsible," he said.

"Bartomeu is certainly partly to blame for the situation, because a president also has the task of establishing a close relationship with the team's protagonists, with the coach and the captains.

"Over the years, he has not succeeded in this. He could not prevent Messi from seeing a change of club as the only alternative for himself. That is a disaster. However: there is never just one guilty one."

The Messi saga continues a tempestuous couple of weeks for Barcelona in the wake of their humiliating 8-2 Champions League defeat to Bayern Munich.

Head coach Quique Setien followed sporting director Eric Abidal out of the door, while Luis Suarez is one of a number of senior players Koeman is thought to have deemed surplus to requirements.