Barcelona’s announcement that Lionel Messi would be leaving the club set Paris Saint-Germain scrambling to figure out if it could sign the most desired free agent in soccer history.

Messi called PSG coach Mauricio Pochettino, who is also from Argentina, on Thursday, a person with knowledge of the situation told The Associated Press. The person spoke on condition of anonymity because the person was not authorized to discuss private discussions.

The person said PSG was assessing the potential revenue that could be generated by signing Messi while also paying him a huge salary and complying with soccer’s financial regulations.

Funded for a decade by Qatari sovereign wealth, PSG is one of the few clubs in the world that can afford the 34-year-old Messi’s salary. A challenge would appear to be ensuring ongoing compliance with UEFA’s Financial Fair Play rules, although some flexibility has been provided due to the pandemic and changes are due to the system designed to stem losses. It is PSG President Nasser Al-Khelaifi who, as chairman of the European Club Association and a member of UEFA’s executive committee, is involved in the process of discussing a wider update to FFP.

Read: End of an era: Barcelona says Messi won’t stay with the club

PSG’s most recent published accounts, covering 2019-20, show the wage bill was 414.4 million euros ($488 million) on a revenue of 560 million euros ($659 million) as it already pays big salaries to Neymar and Kylian Mbappé.

It leaves open the possibility of the exit announcement being reversed if Barcelona can convince the league to back off. But Barcelona’s debts exceed 1.2 billion euros ($1.4 billion), a plight not caused by the pandemic but exacerbated by the lack of revenue from empty stadiums on top of years of financial problems.

While Barcelona’s social media accounts paid tribute to his career, Messi has yet to post anything online about leaving the club he has been at since the age of 13, winning 35 titles. He helped the club win the Champions League four times, the Spanish league 10 times, the Copa del Rey seven times and the Spanish Super Cup eight times.

If PSG was to sign Messi, he would be reunited with former Barcelona forward Neymar. He would also be the latest free arrival at the French club this offseason, following goalkeeper Gianluigi Donnarumma, defender Sergio Ramos and midfielder Georginio Wijnaldum. Like Messi, their contracts expired at Milan, Real Madrid and Liverpool, respectively.

Manchester City, which is owned by the Abu Dhabi royal family, may have the desire and connections to sign Messi. But reuniting him with former Barcelona coach Pep Guardiola could be complicated financially with the Premier League champions breaking the British transfer record on Thursday by signing Jack Grealish for 100 million pounds ($140 million).

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Guardiola all but ruled out the possibility of signing Messi, and referenced the outlay for Grealish.

“Right now, it’s not in our thoughts, absolutely not,” Guardiola said on Friday at a news conference.

Guardiola said he hasn’t spoken to Messi.

“In the end it was surprise for everyone, me included of course,” he said. “The president, (Joan) Laporta, was clear today the reasons why. I didn’t speak with the player or the president so I don’t know what happened.”