Sir Alex Ferguson accused Beckham of becoming distracted by his celebrity lifestyle in his recently-released autobiography.
"It's funny, he was one of the first names I was going to call up to be manager. I'm not so sure now," the former England captain said.
Speaking at an exclusive global digital book signing on Facebook today, the 38-year-old insisted he did not want to speak negatively of his former manager:
"All joking aside I wouldn't want to be negative about Sir Alex. He gave me the chance to live my dream."
Beckham also revealed that after leaving Manchester United he could not face watching them play for two years.