Place pineapple juice in a large resealable plastic bag; add pork chops. Seal bag and turn to coat; refrigerate for up to 2 hours.
Drain and discard marinade. Combine the rosemary, garlic powder, salt and pepper; sprinkle over chops.
Peel and core pineapple; cut into eight spears. Grill chops and pineapple, covered, over medium heat for 4-5 minutes on each side or until a thermometer reads 145° and pineapple is tender, basting occasionally with teriyaki sauce. Let meat stand for 5 minutes before serving.
Arrange spinach on a serving platter; serve with pineapple and chops. Yield: 4 servings.