Barcelona endured a chaotic summer as players took pay cuts, it lost $105 million on a transfer, and sold Messi

• FC Barcelona endured it's most chaotic summer transfer window ever.
• It lost Lionel Messi and players were forced to take pay-cuts to register new signings.
• On deadline day, it sold Antoine Griezmann for $105 million less than it paid for him.

FC Barcelona's summer of chaos came to an ugly head on transfer deadline day as it agreed to sell Antoine Griezmann back to Atletico Madrid for $105 million less than it paid for him just two years ago.

The French striker left Atletico to join Barcelona in 2019 for a $149 million fee, however, the player has since struggled for form at the Camp Nou, scoring just 35 goals in 102 games.

He re-joined his former club on-loan just moments before Tuesday night's 11 p.m. deadline, though there is an obligation for the deal to become permanent next summer for $47 million.

To replace Griezmann, Barcelona made the surprise signing of Sevilla striker Luuk De Jong.

De Jong, who scored just four goals in La Liga last season, joined on a season-long loan with the option of a permanent transfer.

-FC Barcelona (@FCBarcelona) September 1, 2021

The club's deadline day business was exemplar of what has been a woeful summer in Catalonia.

French soccer expert Julien Laurens described Barcelona's exploits this summer to ESPN as "maybe the worst transfer window of all-time."

Lionel Messi, Barcelona's greatest ever player, became a free agent and joined Paris Saint Germain after the club was unable to register him due to the Spanish Football League's (LFP) financial fair play rules.

The club, which currently has $1.4 billion of debt, needed to reduce its wage bill by $237 million to register the Argentine and its new summer signings Memphis Depay, Eric Garcia, and Sergio Aguero with the league.

After Messi's departure and club legend Gerard Pique agreeing a pay-cut, Barca was eventually able to register Depay and Garcia, who joined from Olympique Lyonnais and Manchester City respectively.

Aguero, another City import, however, only registered on Tuesday when another two of Barcelona's longest-serving players agreed to take pay-cuts.

"The salary reductions for Sergio Busquets and Jordi Alba, two of the four first team captains, signed this Tuesday have allowed FC Barcelona to achieve two objectives: the registration of Sergio Aguero with the Spanish Football League (LFP) and to extend the Club's limit with regards to financial fair play regulations," a club statement said.

"Sergio and Jordi Alba have agreed to changes in the financial terms of their contracts which included a wage reduction for this season and the deferment of payments for the remaining years."