You can't just play paddy cake
It works for the Irish.
Actually, you can skip preseason and be perfectly fine, and I don't put much stock in what this Dr. Choad says. That PhD means very little to me when he's just using it to snipe Tweets from afar.
You don't acclimate to collisions and contusions by doing more of it. You don't condition yourself for more of it. The ONLY thing you can acclimate to is asking the body for suddenness and going full-tilt repeatedly, which is 50% a function of the central nervous system and the rest is just maintaining flexibility and elasticity and there's just no way these guys aren't maintaining that level of effort. That's what training is. Taking hits isn't going to prevent injury.