As a caveat, we never know how these kids will turn out, ya know? That said...
A year ago I might have agreed with you on some fronts. But, there's a few things here that I don't agree with.
37 hit it on the head, he isn't a guy without a position. You're right, he's not going to crack the depth chart for the RB's. But, if you consider he's getting close to 6' and starting to get close to that 190-200 mark? He's getting close, body wise.
I see him as a SAM. He's said that he sees the LB position as his best chance to contribute early and at Sam we really don't have a lot of depth there: Atchinson and Tana are the two that come to mind.
Last but not least, while he wasn't big enough to crack any depth chart coming out of high school he's dropped a lot of that "baby fat" and is more svelte than he was when he arrived. Kid is growing up.
Honestly, I'm seeing him like Jerrell or Eryk during their senior years.