The Rams needed to add another CB for depth and they have done just that here in the 5th round. Many thought they would be after a RB, but they went with the best player on their board.
I know nothing about this prospect, and I won't pretend I do. McGee is 5' 11", 193 lbs and he has good speed. He ran a 4.4 forty at the combine. He has good quickness because he has a smaller frame, but he also lacks good strength because of that.
The Rams obvious think they can coach him up to be a good player. You can't coach speed. He will not be forced to play right away with Janoris Jenkins, Cortland Finnegan and Trumaine Johnson ahead of him. He will have time to develop.
Welcome the newest Ram, Brandon McGee. May the whole league know who you are someday.