To prepare steak, coat porterhouse steak with Worcestershire. Cover and marinate steak in refrigerator 30 minutes, turning occasionally.
Prepare grill with one side on medium heat and one side on high heat.
Remove steak from Worcestershire; discard Worcestershire. Sprinkle steak with 1 teaspoon salt and 1 teaspoon pepper; let stand at room temperature 15 minutes. Place steak on grill rack coated with cooking spray over high heat; grill 3 minutes on each side. Turn steak and place over medium heat; grill 3 minutes on each side or until desired degree of doneness. Place steak on a platter. Rub butter over top of steak; let stand 10 minutes.
To prepare fries, combine 1 teaspoon salt, paprika, 1 teaspoon pepper, garlic powder, onion powder, and chili powder. Combine oil and potatoes in a large bowl, tossing to coat. Sprinkle potatoes with paprika mixture; toss gently to coat.
Place potatoes on grill rack coated with cooking spray over medium heat; grill 18 minutes or until sweet potatoes are tender, turning occasionally. Remove sweet potatoes; keep warm. Grill baking potatoes an additional 6 minutes or until tender.