Grilled Portobello Mushrooms in Teriyaki-Ginger Sauce

1. 1/2 cup low-sodium teriyaki sauce
2. 2 teaspoons ginger root, minced fine
3. 4 tablespoons balsamic vinegar
4. 12 ounces Portobello mushrooms, sliced 1/4-inch thick

Mix teriyaki sauce, ginger and balsamic vinegar together in a large ziplock plastic bag. Add mushroom slices. Let marinate for 15 to 30 minutes. Remove mushrooms from marinade and grill 3 to 5 minutes.