Cook rice according to package directions; set aside.
Sauté green onion, celery, mushrooms, and parsley in 1/2 cup butter until tender. Combine sautéed vegetables, rice, pecans, salt, sage, thyme, and pepper; mix well. Set aside.
Remove giblets and neck from turkey; reserve for other uses. Rinse turkey thoroughly with cold water; pat dry.
Stuff dressing into cavity of turkey; close with skewers. Place remaining stuffing in a greased 2-quart casserole. Cover and refrigerate. Tie ends of legs to tail with string or tuck them under band of skin at tail. Lift wingtips up and over back, tucking under bird securely.
Brush entire bird with 1/4 cup melted butter; place breast side up on a rack in a roasting pan. Insert meat thermometer in breast or meaty part of thigh, making sure it does not touch bone. Bake turkey at 325° for 3 hours, basting frequently with remaining butter. Cut string or band of skin holding drumstick ends to tail. Bake reserved stuffing and turkey an additional 30 minutes or until drumsticks are easy to move and meat thermometer registers 185°.
Remove stuffing and turkey from oven. Transfer turkey to a serving platter. Let stand 15 minutes before serving.
Note: Leftover turkey may be refrigerated for later use.