I think the pressure is potentially mitigated by a few things though:
1) He doesn't HAVE to play until he's ready. We may not like Cam (and he may not be ultimately the team's preference at this point), but with an improved roster there's no reason we can't go 5-4 or 6-3 against the schedule we have. The only game that looks inherently "unwinnable" in the first 9 is Tampa Bay (just too much talent and continuity there to overcome in the early season). Other than that Miami in week 1 is tricky because division games in week 1 are always hard to predict, and @LA could be tough due to travel and a coach who might actually remember ST is part of the game. But overall the early season games are pretty tame, which is beneficial either to a team playing with Cam, or a team trying to get a rookie up to speed.
2) The offense has been built to minimize (as much as you can in this era of football) how much your QB needs to carry it on his back. Top 5 starting OL unit, solid stable of RB, two versatile TE's and one of the few teams that still carries a pure FB. It won't be the Greatest Show on Turf, but it's the kind of offense you can run effectively while still easing your young QB along in his responsibilities.
3) The defense last year was 7th in points allowed and middle of the pack in yards. They've added pieces that, even if only half of them contribute as we hope, still should improve the team, ESPECIALLY on run defense. This means not having as many desperation "Oh my god, I've got to throw us back into this lop-sided game!" moments for the rook, as well as turnovers that provide manageable field position. Parallel to this, the Pats still have one of the best ST groups in the league.
Winning a Super Bowl is definitely a stretch for this year, but it's not hard to imagine a path to being right in the mix come playoff time.