Preheat oven to 400°. Sauté sausage in hot oil in a large skillet over medium-high heat 4 to 5 minutes or until browned; drain.
Melt butter in a large skillet over medium-high heat; add celery and onions, and sauté 5 to 6 minutes or until onions are tender. Stir in sage, and sauté 1 minute.
Stir together Cornbread Crumbles and breadcrumbs in a large bowl. Stir in eggs, next 3 ingredients, sausage, and celery mixture, stirring until blended. Divide cornbread mixture between 1 lightly greased 13- x 9-inch baking dish and 1 lightly greased 8-inch square baking dish.
Bake at 400° for 45 to 55 minutes or until set and golden brown.