That's a really awkward hit, but I don't see it being suspendable or even a penalty.
Doughty made an ordinary approach to the hit, squared the guy up, led with the shoulder, had a good deep knee bend at the time of contact, and he didn't launch up into it or anything like that. He actually slowed down very slightly before the hit, so there's not even a charging call there. Everything about the way he led into it was textbook, just the way you'd coach it.
The only reason for the head contact was Carrier's trying to pull up at the last possible half-second, while he was still in a leaning-forward position. If Carrier just commits to the play he takes that hit square on the shoulder... gets posterized maybe, but doesn't put himself in a dangerous position.
I realize the league puts a heavy onus on the hitter to avoid making head contact, but I don't know what you expect Doughty to do differently here. Try to clip Carrier instead, aiming for the knees? Try to hit him in the butt?