Preheat oven to 475°.
Place garlic in a small saucepan, and cover with water. Bring to a boil; remove from heat. Drain and cool slightly. Make several small slits on outside of fillets; stuff with garlic. Place fillets on a broiler pan coated with cooking spray.
Combine butter, sage, salt, and pepper; spread evenly over fillets. Bake at 475° for 13 minutes or until fish flakes easily when tested with a fork.