1Heat gas or charcoal grill. In medium bowl, mix pork, seasoning and 2 tablespoons reserved pineapple juice. Shape mixture into 4 patties, about 1/2 inch thick.
2Place patties on grill over medium heat. Cover grill; cook 6 to 7 minutes, turning once, until no longer pink in center and meat thermometer inserted in center of patties reads 160°F. During last 4 minutes of cooking time, add pineapple slices to grill, turning once.
3On bun bottoms, place lettuce, burger and pineapple slice. Cover with bun tops.