UFC's Frankie Edgar -- Let's Get Shaq In the Octagon ... He's Got Real Talent!

He can hoop, he can rap, he can act (sorta) ... but can Shaquille O'Neal fight MMA?!

There's one UFC superstar who believes in the Big Fella ... Frankie "The Answer" Edgar ... who tells TMZ Sports he thinks O'Neal's got what it takes to SERIOUSLY compete in the octagon.

"He's so big," Edgar said on his way out of a Toyota party ... "He's a pretty good athlete. He can box too probably."

BTW -- Shaq's only 43-years-old ... that's 3 years YOUNGER than Randy Couture was when he fought James Toney at UFC 118. Couture also fought Lyoto Machida when he was 47.

So, will Shaq ever really fulfull his potential? Probably not ... unless this Shaq vs. Charles Barkley mega-fight ever goes down.

#FingersCrossed