Preheat oven to 375 degrees.
Remove whole leaves from cabbage to yield 20 large leaves and plunge into boiling water. Cook until soft enough to fold, about 4 to 5 minutes. Drain and rinse with cool water and lay out on clean kitchen towel to continue cooling.
Meanwhile, in a large mixing bowl, place ground turkey, 1/2 cup bread crumbs, 1/4 cup parsley, red onion, sage, salt, pepper and eggs and mix well with hands. Lay out cabbage leaves on cutting board on counter and place a medium handful of turkey mixture in lower center of each leaf. Fold lateral sides inward and roll from base to form a closed pocket out of each stuffed leaf. In an oven-proof casserole, large enough to just hold all cabbage rolls, place half the tomato sauce and all the white wine. Lay cabbage rolls on top of sauce until covered with one layer. Spoon remaining sauce over and bake 1 hour. Remove and sprinkle with remaining bread crumbs and parsley. Serve immediately.
Saute the onion and garlic in the olive oil over medium heat until translucent, but not brown (about 10 minutes). Add the thyme and carrot and cook 5 minutes more. Add the tomatoes. Bring to a boil, lower the heat to just bubbling, stirring occasionally for 30 minutes. Season with salt to taste. Serve immediately, or set aside for further use. The sauce may be refrigerated for up to one week or frozen for up to 6 months.