I voted that he'll be back before the first game. I think that his decision will hinge somewhat on word out of camp. How Wilson, Gay, Meriweather or Scott looks at the spot.
If the secondary performs well the first two preseason exhibitions, I can see him hurrying in to make sure doesn't lose the guaranteed money nor his spot on the roster.
If the secondary suffers some injuries or the plan doesn't look to be panning out, I can see him waiting till week 10 to come back. He'd maximize his future earnings while minimizing his risk by doing so, and still have a chance to shine in the playoffs.
I do not see BB cutting his nose off to spite his face, by benching Samuel for the balance of the season. For one reason, it's against the rules these days. For another, BB has always said he plays the guys that can do the job, in practice & on the field. Once Samuel practices for 3 to 4 weeks, he'll be ready to contribute in December.
I don't think there's more than a slim chance that he'll be traded this year, nor that BB will waive the right to tag him again next year. It's easier to plug in one or two receivers into the starting lineup than it is to do so at LCB. It would not be worth it to the pats, unless some team was willing to offer more than one #1 pick.