Place chicken between 2 sheets of heavy-duty plastic wrap, and flatten to 1/4-inch thickness using a meat mallet or rolling pin. Set aside.
Cook sausage in a large skillet over medium-high heat 10 minutes or until it crumbles and is no longer pink; drain and set aside.
Prepare Alfredo sauce according to package directions; set aside.
Combine shredded mozzarella and Parmesan cheeses.
Stir together sausage, spinach, ricotta cheese, and 1/2 cup mozzarella cheese mixture. Spoon mixture evenly down center of each chicken breast, and roll up, jellyroll fashion. Arrange chicken rolls, seam side down, in a lightly greased 2-quart baking dish. Pour Alfredo sauce over chicken, and sprinkle evenly with remaining 1 1/2 cups mozzarella cheese mixture.
Bake at 350° for 50 minutes to 1 hour or until chicken is done. Let stand 10 minutes. Cut chicken rolls into slices. Serve with sauce; sprinkle evenly with diced tomatoes just before serving.
Note: For testing purposes only, we used McCormick Creamy Garlic Alfredo Pasta Sauce Blend.