I'm not sure how much of a chance he stands at DB or WR.
WR we have Ryan Williams, Bernard and Horton as a clear top 3. And then Scott and Brooks have both made some noise at different points.
Just at CB we have Domani, Brown, Calhoun & the apparent star of a TF in Dijon Lee. Then at S we have Sabb, Hubbard as the clear top 2. DaShawn Jones is the expected nickel. Then we have a bunch of other talented guys he would have to battle ,even if some of them are TF, in Mincey, Kirkpatrick Jr, Ivan Taylor, Red Morgan even Chuck McDonald.
I know Mbakwe was a 5 star and is talented but I'm not 100% where he lands on our depth chart at any position he would play. I would be moderately surprised if he is a significant contributor this year.