#5 Ronaldinho (Summer 2003)
As David Beckham swapped Manchester for Madrid, United were in need of someone to replace the England international. Sir Alex Ferguson had decided that it would be with Ronaldinho, who was set to move away from Paris Saint-Germain.
Everyone at United, including the manager thought they had their man, only for the Brazilian to choose Barcelona despite professing that he "would like to be at a great club like United". Years later, the Brazilian playmaker revealed how close he was to signing for United and why he chose the Catalan club instead.
"I was on the brink of joining Manchester United, there were just a few details to iron out, but Rosell called me at the last minute to tell me that they were going to win the election," he said. "And I had promised to him that I'd play for Barca. It was a quick negotiation. I told the English I had chosen Barca."
In the end, United missed out on a future FIFA Ballon d'Or not due to another player or manager but due to a friend of Ronaldinho's, Sandro Rosell.