MLS commissioner Don Garber said: "David was really a home run for us, to use a baseball analogy.
"And a lot of that has to do with him being quite the celebrity. If I was a sponsor, I would want him to represent me because he's just a quality guy.
"I hope to see at some point, certainly during my tenure as commissioner, players like that in Major League Soccer. And with Beckham being successful and being signed, it's hard to imagine you wouldn't see players like that in MLS."