I dont think they will assign Newman to anybody, just whoever is on his side. A couple of years ago I would have said put him on Harrison, make Wayne beat us. But at this point the discrepancy between the 2 WR is very small. I say Newman covers whoever, and the other gets doubled.
Another thing that bothers me is that Newman will probably be covering Brandon Stokely in the slot. I know it his job but I would much rather see him on one of the top 2 WR, although Stokely is pretty dangerous.