Currently on roster...
And two more undrafteds.
The number expected to be kept is five, one of which will likely be a special teamer and another of which will probably be Armanti Edwards for return duties. Smith would seem to be a lock (despite the prior trade talk) and likely so is Gettis.
That leaves a bunch of guys fighting for one spot. Naanee is ahead of LaFell on the charts right now and was brought in because Rivera felt no one else was "stepping up". And Clowney has, by several accounts, been impressive so far (again, assuming he isn't just this year's camp flash).
Again, I think he'll stay, but barring injury to someone else, his starting the season elsewhere is not as farfetched as it might seem when you look at the factors.
With the exception of Smith, Naanee, Gettis. Who else is at LaFell's level?
Edwards? No, he's improved, but hasn't shown what LaFell did on sunday.
Adams, Wright, Guy, wallace, Pilares, Warren, Martin? Nope.
Clowney? Yes. Agreeing with your "camp flash" theory.
If something happens, and heaven forbid it does, someone gets injured. LaFell is serviceable. I don't see him being traded. WR position isn't as weak as last year, but if you get rid of LaFell, it would become weak with one Injury. What if Smitty would have broken several fingers? Out for weeks and we would only have Gettis and Naanee? I'd feel more comfortable with LaFell in that mix.