How many backs do we see, EVERY YEAR, that get starts because the starter went down and the come out of nowhere and do damn good. It is just like the QB spot. Brock Purdy would still be sitting on the bench today if Trey lance was even decent. But he got a chance. A real chance, not 5-6 minutes of garbage time at the end of the game.
Backs are the same..... you cant show jack squat in practice. Defenses are hitting in practice, offensive lines arent going full speed. Until you get game time, and real game time.... you will never know what someone can do.