In a large pot or Dutch oven, heat olive oil over medium heat. Add onion, celery, and carrots and cook until softened, about 5-7 minutes.
Add garlic and mushrooms and cook for another 3-5 minutes, until mushrooms are tender.
Add chicken broth, turkey, sage, rosemary, oregano, and bay leaves. Bring to a boil, then reduce heat and simmer for 15-20 minutes to allow flavors to meld.