I think the only way he doesn't make it right off the bat is if both Latendresse and Bouchard are on the opening day roster. Without them, we have no 2nd line wings, so he could slot in alongside Granlund and Cullen.. Even if one of those guys comes back, he could play with Clutter and Brodziak on the 3rd line.
He'll probably be battling with Larsson for that last top 9 spot.
I think you haven't looked at the depth chart recently. Assuming Granlund starts at wing (which is pretty much a certainty at this point:
Heatley-Koivu-Granlund
Seto-Cullen-[Open]
[Open]-Brodziak-Clutterbuck
Johnson-Powe-Kassian
Even if Granlund starts at center, that will move Cullen to wing, likely on the 2nd line (unless we sign someone for the top 6
and have another rookie amaze):
Heatley-Koivu-Seto
Cullen-Granlund-[Open]
I'm expecting one of Lats/Butch to be available, which fills our top 6. The only way Coyle makes the team out of camp is if he beats out both Larsson and Bulmer for the last open spot, we don't sign anyone, at least one of Lats/Butch isn't playing, and nothing surprising happens with the 4th line and our "lesser" prospects.
Unless the team is determined to have Bulmer play in Houston to continue to develop his offensive game, the only prospect I can see beating him out is Larsson, unless Coyle steps in and does well enough to threaten Granlund's spot on the roster.