Preheat oven to 400 F. Spray 13X9 inch cooking pan with nonstick cooking spray. Combine potatos, onion, carrots, butter, salt, garlic powder, thyme and pepper in a large bowl. Toss to coat evenly. Place mixture in greased pan, cook uncovered for 30 minutes. Add sausage to mixture, combining well. Continue to bake 15-20 minutes or until potatos are tender and golden brown.