Splatterface is a boy who used to be the batter of the Springfield Isotots.
Nelson told Lisa that Splatterface used to be a very good batter in their team, but left after he had been bullied by other members. Nelson sees Splatterface was walking past and shouts, "Hey, Splatterface, how is the weather up there?" He looked sad and went away.
Nelson then says that it was a shame, as he was a good batter, but it was worth it.