Place chicken in a ziploc bag and pour in the Teriyaki sauce. Seal and place in refrigerator overnight.
Prepare your grill and cook chicken over direct heat, turning every 5 minutes. When chicken is almost done cooking, place a pineapple ring on each piece and top with melted butter. Using a brush is easy. Close lid and cook for 3 minutes. Remove and let cool.
In a smallsaucepan over medium heat, combine the brown sugar, soy sauce, pineapple juice,and Worcestershire sauce. Stir until the sugar is completely dissolved. Turnoff the heat and allow it to cool.