Dave Roberts challenged his team and guaranteed a World Series championship When you make a guarantee, you have to pull through with it unless you want to look foolish. For Dave Roberts, he guaranteed the Dodgers would win a World Series during Spring Training on a national radio broadcast. Will Dave Roberts look foolish if this guarantee isn’t met? Probably not, but from the beginning of the season he put a target on the Dodgers back with a vicious claim to the promised land. Even with such claims, Roberts was asked by reporters again of his aspirations but of course…