In large pot, melt half of butter over medium-high heat; brown turkey in 2 batches, adding more butter as necessary. Transfer to bowl. Reduce heat to medium; add remaining butter to pot. Cook carrots, onion, celery, thyme and sage stirring, for about 5 min or until onion is softened. Stir in rice.
Add stock and tomato paste, scraping up any bits stuck to pot. Cover and bring to boil over high heat. Reduce heat to medium-low; boil gently for 15 min or until rice is almost tender. Stir in turkey and any juices and cook, uncovered, for about 5 min or until rice is tender.
Increase heat to medium. Whisk flour into milk; gradually whisk into soup. Cook, stirring, for 3 min or until slightly thickened and turkey is no longer pink inside. Stir in salt and pepper to taste.
