The six-time Ballon d'Or winner last week informed Barca of his intention to leave, however, La Liga disputed Messi's claim that he could leave on a free transfer courtesy of a clause in his contract.
The clause meant any club wanting to sign Messi had to negotiate with Barca or pay his $1.1billion dollar release clause.
After days of chaos, Manchester City looked to be the frontrunners and had made an offer to sign the superstar, to which Barcelona refused as they looked to stand firm on keeping their star man.
Messi announced on Friday that he will in fact remain at Barcelona because of the financial demands made by the board.
Mexican legend Sanchez, blamed the 33-year-old's failed exit strategy on his representatives.
"That untimely burofax only strengthened the image of the president of Barcelona and gave him time to weaken Messi's decision," he told ESPN.
"Messi has had no choice but to stay at Barcelona due to bad advice from his father and the law firm, because they could have saved that burofax. That has caused weakness to his image within the team.
"Coincidentally, Messi had the lawyers who had previously worked with Barcelona, but due to a conflict of interest, the Catalan club changed its strategy.
"If Messi and his father already had the decision to leave Barcelona, they should not have waited in time.
"But before the end of the term agreed in the contract, they had to tell the club that they wanted to leave at the end of the season and on a free, without paying any compensation. If they had it planned, it should have been done that way."
Messi will now weight up his future at the end of the 2020-21 season.
"Messi likes to win titles and will need to look for another team where he can win championships and prove that he is the best player ever," Sanchez said
"The whole problem with Barcelona is going to distract him next season
"Fact is he is not the same young man who ran all over the pitch."