Place fillets in a large baking dish; season with olive oil, salt and pepper. Bake for 20 minutes or until fish flakes easily when tested with a fork.
In a small saucepan, combine grapefruit juice, honey, rosemary and garlic. Bring mixture to a boil then lower heat and cook for 5 to 10 minutes, stirring constantly, until thickened.
Place salmon on a bed of lettuce leaves; drizzle sauce over the top. Serve warm.