The napkin was signed in December 2000 when Carles Rexach, then Barcelona's sporting director, agreed with agent Horacio Gaggioli to recruit the Argentine teenager who went on to become the club's all-time top scorer.
Bidding for the document, described by auction house Bonhams as "blue ink on a standard Spanish waxy napkin," was at £220,000 shortly after the sale opened, according to the auctioneer's website.
The online sale closes on May 17th and has a guide price of between £300,000 and £500,000.
"It was never legally binding, but emotionally it represents the deep link or the beginning of the deep link, that Messi had with Barcelona," said Bonhams Chief Marketing Officer Marc Sands.
Messi helped Barcelona win 35 titles, making a record 782 appearances and scoring 674 goals. Messi left Barcelona in 2021 and now plays for Inter Miami.
"If you love football, you'll know all about Lionel Messi and you will know that he defined football for generations. If you want a slice of that action, this is the thing to get,” Sands said.
