John

Roger is a character of the day who appeared in Stage Fight! (EP092). He was the organizer of the Pokémon Showboat, where Pokémon would act out a play and humans would provide the voices of them.

One night, Team Rocket came aboard the boat and tried to steal all the Pokémon. In the ensuing battle, Weezing used a Smokescreen attack. Initially, it didn't appear to affect anything, but the next day, Roger had lost his voice because of it and could not perform his part in the show. Kay, another member of the Pokémon Showboat, convinced Ash and his friends to help out. Ash took Roger's place and the performance went on without any problems.

(Source: Bulbapedia)