...that just leaves Chase more open. When they are focused on where Marion is lining up, is he going to run it or run a pattern, etc., it just gives the defense more to worry about. And them worrying about more stuff makes it easier for Chase to have 1 on 1 coverage on 3rd and 10.
So yeah - Chase Roberts will be the #1 receiver - but won't it be awesome having multiple dudes who can produce at the WR position?