Lil Wayne & Ronaldo ... 'It Might Be a Great Partnership' ... Says Common

Lil Wayne's sports management company has the potential to be HUGE -- and going after Cristiano Ronaldo to be client #1 could make for a "great partnership" ... so says rap superstar Common.

We broke the story ... Wayne is all set to handle Ronaldo's U.S.-based sports management needs (branding, marketing, etc.) ... a move Common thinks is smart because of Weezy's track record.

"Obviously, [Young Money Cash Money Billionaires] is very successful ... so, you know, it might be a great partnership."