I can't directly comment, Woody, as I have not seen proof, per se (e.g., closely watching every play on offense, every game), that he definitely hasn't been on the field yet.
But assuming your recollection is accurate, it is at least somewhat disconcerting. Not only because of the hype over the improvement he showed all spring with his monstrous body, but because his dad is RB coach, and wouldn't (1) show any favoritism, nor (2) tolerate any "nonsense".
Injured, perhaps?
Obviously, he is not (nor is anyone) going to shove BIG JAKE to the bench, but Jimbo loves the two-TE sets...and as good as Gentry may be playing, you would think there would, at least some of the time, be room for a 290-pound blocker out there...