Break turkey frame or cut in half with kitchen shears. Place in an 8- to 10-quart kettle or Dutch oven. Add water, onions, celery, bouillon granules, and garlic. Bring to boiling; reduce heat. Simmer, covered, for 1-1/2 hours.
Remove turkey frame. When cool enough to handle, remove meat from bones. Discard bones. Coarsely chop meat. If necessary, add enough turkey to equal 2 cups; set turkey aside.
Strain broth, discarding solids. Skim fat from broth. Return broth to kettle. Stir in undrained tomatoes, oregano, and pepper. Stir in vegetables. Return to boiling; reduce heat. Simmer, covered, for 10 minutes. Stir in noodles. Simmer, uncovered, for 8 to 10 minutes more or until noodles are tender but still firm and vegetables are tender. Stir in turkey; heat through.