I've been following this a little bit, and DC3 injured his ribs in the first preseason game which didn't help his cause. Even before the preseason Arians traded for Moore who is a back Arians is familiar with having worked with him previously if I recall correctly. And Vick Ballard has opened eyes from the day he was drafted. If the Colts go with 4 RBs I think DC3 makes the cut, but it will be close.
If the Colts let him go I suspect Delone will end up with another team. Ironically, I think those fumbles last year hurt him in the eyes of the new coaching staff. I say ironically because DC3 almost never fumbled at SU. He just needs to secure the ball and trust his abilities and I think he ends up someplace this year.