Thats a great sign of maturity in Lewis, in my opinion. He understands that stepping outside of your comfort zone is an important aspect in facilitating growth as an individual (and as a football player).
Bold prediction:
Kamara returns. He and Hurd split carries more evenly. Hurd has another good season, with numbers similar to this year. Next years NFL RB class is super deep and Hurd decides to stay for his senior year and subsequently breaks every UT rushing record in the books along with...
That was my point, it's not an issue right now.
I agree that if DY is our second back we could have problems. That being said, I think he could be a fine 3rd down back.