Manchester City are confident Lionel Messi would snub any other team's effort to sign him if Barcelona soften their stance and decide to negotiate the sale of the six-time Ballon d'Or winner, sources have told ESPN.

Paris Saint-Germain have expressed an interest in signing Messi, too, and sources have told ESPN that Neymar talked to him over the phone on Thursday about the possibility of a move to France.

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Despite that, City are still the Argentina international's most likely destination if he manages to force a move away from Camp Nou. Sources have told ESPN that Messi has requested a meeting with the Barca board to facilitate his exit.

City are aware that completing any deal will be extremely difficult because of Barca's reluctance to sell and the cost of the operation. However, they are hopeful the Catalan club will eventually cede and agree to let Messi go for a reasonable price, given his desire to leave.

Sources told ESPN that Messi called coach Pep Guardiola last week to tell him he wanted to leave Barcelona after nearly 20 years at the club. There is still no agreement between City and Messi, but the club speak almost daily with his father, Jorge, and are working on a number of possible formulas.

The first, as reported by ESPN earlier this week, would see Messi sign a three-year deal with City, with the option to then move to partner club New York City FC for another two years at the end of his career.

Another idea on the table is an initial two-year deal with the possibility of an additional year based on a number of different objectives. Other options also have been discussed. Messi's father is still in Argentina but is expected to fly to Europe soon as negotiations pick up their pace.

City know the option of signing Messi for free is remote. Messi told Barca he was executing a clause in his deal that would allow him to walk away for nothing, but the La Liga side insist said clause expired in June.

As reported by ESPN earlier this week, City would be willing to pay between €100 and €150 million, which is substantially less than the €700m buyout clause in his contract, which expires in June 2021.

City would be willing to include certain players in any potential deal, but sources close to the club stressed that Bernardo Silva, Gabriel Jesus and Riyad Mahrez would not be used as makeweights in any potential transfers this summer.

Messi is due at Barca's training ground on Sunday for a coronavirus test ahead of the start of preseason under new coach Ronald Koeman on Monday. It's not yet clear whether he will turn up.

Barca were first informed by Messi that he wanted out on Tuesday. On Thursday, president Josep Maria Bartomeu leaked that he would resign if that's what it takes to get Messi to perform a U-turn on his decision.

Bartomeu said he would step aside and leave the board of directors in charge until March's elections if Messi said in public that Bartomeu was the problem. There has been no response from the Messi camp, but sources told ESPN that Messi will speak about the reasons he wants to leave at some point. There are no plans to say anything imminently, though.

Messi's desire to leave is rooted in problems on the pitch -- especially failings in the Champions League since 2015 -- and off the pitch, where he has clashed with the board over a number of issues.