Complex sentence: The Mets played along with the hoax, even providing a uniform for Joe Berton, a junior high school art teacher from Oak Park, Illinois, who posed as "Finch" for the photographs (usually with his face averted from the lens).
Split into simpler sentences: The Mets played along with the hoax, even providing a uniform Finch. Berton posed as "Finch" for the photographs (usually with his face averted from the lens).