Heat oven to 400°F. In 10-inch skillet, cook sausage over medium-high heat 5 to 7 minutes, stirring occasionally, until no longer pink; drain. Add onion and saute until tender and golden, about 5 minutes. Add bell peppers and carrot and saute an additional 2 minutes. Stir in pasta sauce. Season with salt, pepper, and oregano. Simmer while you prepare the remaining ingredients.