The 6'1", 180-pound receiver has now signed aid agreements with Georgia, Georgia Tech and Cal, but remains the last uncommitted five-star recruit in the class of 2016.
Scout ranks Robertson as the No. 23 recruit in his class and the No. 3 wide receiver.
Robertson is expected to make his decision this month, and was reportedly awaiting the results of his SAT test before choosing a school.
He has taken official visits to Alabama, Notre Dame, Cal and Georgia Tech.