To be fair, isn’t Luke around 6’2”? Pretty tall for a running back as I cannot see him putting in the requisite weight at that height (230ish) to have an effective body to take the pounding a running back takes. Plumlee, on the other hand, is 6’ and if he can bulk to 210-215 lbs he would be dynamite. He runs a legit 4.3 and just plays faster than everyone else on the field.
He will play either running back or slot… honestly he could be a Percy Harvin-type if player. Or Deebo Samuel… only 2/3 running 1/3 receiving rather than Debo’s opposite ratio.