Barca's surrender to Real Madrid in LaLiga's title race and the 8-2 thrashing at the hands of Bayern Munich in the Champions League proved the final straw for Messi.
A meeting with new head coach Ronald Koeman last week was not enough to convince the six-time Ballon d'Or winner to remain at Camp Nou.
We consider what Messi's next destination could be.
Newell's Old Boys
Messi's relationship with the public in Argentina has often been strained due to the fact he moved to Barca at the age of 13 and was moulded in their famous La Masia academy.
But he started out at Newell's five years prior to that and a return to his hometown of Rosario would be an understandable move as he enters the latter stages of his career.
While the 2019-2020 season may have been a disappointment, Messi undoubtedly still has the quality to play at the highest level. City, managed by former Barca boss Pep Guardiola, are said to be looking into the feasibility of bringing the Argentina superstar to the Etihad Stadium, having in July won their appeal against a two-year Champions League ban for breaches of Financial Fair Play regulations.
"Which coach says no to Messi?" said PSG boss Thomas Tuchel following its UEFA Champions League final defeat to Bayern on Monday (AEST).
The Ligue 1 champions has never shied away from splashing the cash – it paid Barca a world record €222million for Neymar and shelled out €180m on Kylian Mbappe. If Messi wants to win another Champions League title before retiring, few clubs are better positioned to help him achieve that.
Even before there was any doubt about Messi's future at Barca, Inter was the main club linked with an audacious attempt to sign the 33-year-old.
The Suning Holdings Group ownership makes them one of the few clubs alongside City and PSG that have the financial capacity to offer him a sizeable contract, and they have secured a return to Champions League football next season. The chance to battle old foe Cristiano Ronaldo in Serie A could prove an enticing prospect too.
They may be bottom of the Eastern Conference in their debut MLS season, but Inter Miami still have a designated player spot free and there could be no bigger name to fill it than Messi. Club owner David Beckham said in February of this year he would relish the chance to sign a player of the calibre of Messi or Ronaldo.
Things could have gone very differently for Barca had club legend Xavi been handed the reins in January. A link-up with his former team-mate in Qatar could be an option for Messi, though there is every chance former midfielder Xavi finds himself back at Camp Nou in the not too distant future.