Audio problem: When the boys are beating up Mikey during the flag football type game, he knees one of the kids in the crotch. An African American boy then says "man you should start wearing a cup." The boy's mouth doesn't match.
Audio problem: After Bobby says the "F" word, he says "someone get me soap, I'll do it myself." His mouth doesn't match.
Answer: He was in a very small part of the movie and at the time he had already become quite a famous star. If his name were attatched to it without being uncredited, he would have had top billing. He probably decided to remove his name from the movie so the younger actors could receive more attention. The same type of thing happens in quite a few movies I can think of.
jennibee