TMZ Sports has learned ... Ali's grandson, Biaggio Ali Walsh (son of Rasheda Ali Walsh), inked a deal with the Wilhelmina modeling agency ... one of the top modeling agencies in the world.
Wilhelmina has a pretty impressive roster ... with stars like Nick Jonas, Demi Lovato and Charlotte McKinney.
Now, we've confirmed the agency locked up 17-year-old Biaggio ... who also happens to be one of the top high school running backs in the country.