I don't know yet until I see them all in camp and preseason but I would not be shocked if Luepke is one of the 3 active backs on game day at some point. He looks like a nice option out of the backfield. I just don't see them activating Turpin and Vaughn unless one or more running backs gets hurt.
His carries will depend on his performance. If he consistently breaks off good plays, he'll get more carries. If he gets stoned at the line of scrimmage, he'll get less.