In an ideal world, both Jarred Tinordi and Nathan Beaulieu are mature enough physically and mentally for the grind of an NHL season next fall. So we plug them in and they improve by getting their minutes in the NHL, not AHL.
Practically, in our world, where Adam McQuaid gets a grudging, belated two-minute penalty for a(n) two-hand punch/crosscheck/outright attack on Andrew Shaw, right in front of the referees, I don't think our boys are ready. Certainly Nathan Beaulieu, who showed up to camp last season out of shape, and has shown some indiscipline, may not be ready yet for the spotlight and pressure of the big stage.
Another important consideration is that skill development is not just a function of time, of waiting for the calendar pages to flip. You learn skills by doing, by practicing. Progression is important. If you're in an environment where you don't have the time and space to practice these skills, to attempt them in game situations, they don't develop.
For example, take juggling. Most everyone can learn how to juggle, you just need time and practice. YouTube must have great videos to guide you. Anyway, if you have the time, the equipment, and a practice space conducive to learning, you learn how to juggle two balls with one hand, then with the other hand, then three balls with two hands, then maybe against a wall, or bouncing off the floor, or you increase the difficulty with four or five balls. With time and practice, you hone your skills and cut down on errors, and can work with eggs or chainsaws.
If however you're in a situation where every time you try to learn, someone comes out with a camera and points out your mistakes every time you drop a ball, and a bunch of people on a couch laugh and taunt, and an authority figure with a megaphone berates you when you don't learn quick enough, and some people want these balls from you and tackle you to get them, you'll never learn to juggle.
Take the first person who's now juggling with five balls or with chainsaws though, and plug her in that inauspicious environment, and that girl can cope with the increased degree of difficulty from the couch dwellers and Captain Video and the Haranguer in Chief. She can still juggle, and will be able to juggle in most situations.
So back to Nathan and Jarred, if they're in the NHL, and the puck is on their stick with Chris Neil or Jason Spezza bearing down on them, and the scholarly, arch Mike Boone is in the press gallery taking meticulous notes of every miscue, maybe they learn that the best, the only thing to do is to bang the puck off the boards, but quick, and every time. Doing this, they'll keep their head above the raging waters. But they'll never learn to juggle.
In the much calmer AHL pool however, faced with the same situation but going up against Ben Maxwell and Toby Petersen, they can learn to take the half-second to scan the ice for the outlet pass, or to decide to skate around the net while protecting the puck à la P.K. Subban, in addition to the obvious, safe, Don Cherry bang-it-off-the-glass solution.
So if they show up to camp and present the Canadiens with an inescapable conclusion, that they are more than ready, and if they, as Rick Dudley described, win the job outright, then sure they stay up with le Grand Club. Or, if it's not decisive, we play it safe and send them down for further ripening. As Marc Bergevin famously said, we won't regret leaving them in the AHL too long, but we might bringing them up too soon.