In a small bowl, mix together the garlic powder, rosemary, salt, onion powder, pepper and garlic. Using your hands, coat the meat with the olive oil, and then smear the rub all over. Transfer the meat to a plate, cover with plastic wrap and chill in the fridge for at least 1 hour, or up to 4 hours.
Prepare a grill for indirect cooking at 225 degrees F. Remove the roast from the fridge 30 minutes before you are ready to cook, so it can come up to room temperature.
Place the roast on the grill over indirect heat and cook until it reaches an internal temperature of 125 degrees F for medium-rare, approximately 3 hours. Remove from the grill, cover with foil and let rest for 10 minutes before serving.
Bison meat does not marble like cow's meat, so it is a lot leaner. Bison can take a third less time to cook compared to beef and is best eaten rare to medium-rare. Cooking times can vary depending on the thickness of the roast, so I strongly recommend using a meat thermometer.
A viewer or guest of the show, who may not be a professional cook, provided this recipe. It has not been tested for home use.