Fall of the Roman Umpire

In 1980 the Pope made a tour of the United States, and was kidnapped by a group of radical Catholic Reformists from Eastern Europe, and replaced by a ringer; an insane major league baseball umpire.  The Pope escaped his captors, but try to get anyone in New York City to believe that he really is the Pope!  He finally is forced to hustle pool for a living and is at the mercy of the seedier characters of Manhattan. 

Meanwhile, the Vatican is taken over by a pontiff who shouts "Play ball!" at the beginning of mass, and insists that nursery rhymes as just as beneficial as Hail Mary's for penance (or pennants), and popsicles are proper rewards for doing them right.  The heroes of the story are even crazier, with a blind pencil salesman, an FBI librarian, and an interpretive dancer trying to straighten everything out.