Well Ashton Jeanty is listed at 5’9” we will see at the combine. So to answer your question here’s the top 5 all time rushing leader list:
Emmitt Smith- 5’9”
Walter Payton- 5’10”
Frank Gore- 5’9”
Barry Sanders- 5’8”
Adrian Peterson- 6’2”
Currently we could look at the greatest RB in Saints history in Alvin Kamara he measured 5’9.5” at the combine. Or another one of the recent Saints top RB’s Mark Ingram who was also 5’9”.
Of the top 15 RB’s in yards from scrimmage in the NFL this season, 9 of them are shorter than Bijan Robinson.
Jeanty at 5’9” vs Bijan Robinson at 5’11” with both being about 215lbs gives Jeanty the advantage when it comes to size if anything. As mentioned before makes him more compact at the same size, which is likely part of the reason he is so much more effective getting yards after contact.