Combine sage, salt, pepper and garlic. Rub over roast. Place in slow cooker with 1/2 cup water. Cook on low for 6-8 hours. About 1 hour before roast is done, combine ingredients for glaze in small sauce pan. Heat and stir until mixture thickens. Brush roast with glaze 2 or 3 times during the last hour of cooking. Serve with remaining glaze on the side.