I agree Roby is likely gone. Also, I think Morgan edges out Arrington and/or Arrington gets injured and as a result, we have 5 active WR, going into Game 1:
Colston
Henderson
Moore
Toon
Morgan
and then WR roster, likely to vary after Week 1 and each subsequent week. Just guessing (predicting) the outcome.
*Personally, I am hoping that a sleeper rises to the occasion, as well.