How do I defrost a roast quickly?!
You can put the roast directly in the slow cooker on high, just increase the cooking time as another person said. You don't need to worry about bacterial growth in this situation because the meat thaws very quickly when submerged in hot water, and most bacteria is on the surface of the meat, not in the interior, and it doesn't stay in the temp dangerzone long enough for bacteria to grow.
Even better would be to cook the roast in a pressure cooker, which would take less than an hour, including thawing, instead of 3+ hours.
I find soaking the meat in the packaging in a sink full of ice water really helps. I also cook many of my meats from the frozen stage,especially roasts as i find they are more tender that way,i dont use a slow cooker though so i cant say long that would take,i just use my oven.
I always put frozen roasts into the crock pot. Just cook it on high to start with or cook it longer. It will be delicious, it just takes longer. Enjoy your dinner.
The best way is submerged in cold running water, with the wrap on.
Do not start cooking with centre frozen, it boosts bacterial growth.