McCray is not a middle backer.
He is sorta a DE/LB. I was bit surprised he didn't end up on a 3-4 team but Denver offered him quite a bit for an undrafted player.
I think you could see him line up at either LB position most noteably behind Trevathan with Irving behind Miller, and then he may be able to develop into a situational pass rusher. At UF he started as a LB and they found a way to get him on the field by making him a DE.