In large skillet cook rice, celery, green pepper, and onion in butter till vegetables are tender and rice is browned; stir occasionally.
Meanwhile, combine tomatoes, thyme, and cayenne; stir into rice mixture.
Place frozen block of sliced turkey atop rice mixture.
Cover and simmer till turkey is heated through and rice is tender, about 30 minutes; stir occasionally.
Remove from heat; let stand 5 minutes before serving