Robinson was a WR only in title. As far as I can remember, he didn't play a snap at receiver last season and his only purpose on the team was as a return guy. I don't see how this would increase or decrease the chances of drafting Crabtree, which I think is still at about 0%.
Anyways, what do you expect? He was a Herm/King Carl guy brought in for returns only, and didn't show any promise in that area. His return averages were bad, and he had a couple fumbles too if I'm not mistaken. Kind of weird to call him promising, in my opinion.
I didn't expect Will Franklin to be cut, but after Franklin was released it became pretty clear Robinson probably would be too.