After trying to clean up the list, I think I've got all the actual pitchers. Here they are:
|La Marr Hoyt||1984||CHW||*1/7|
The positions column tells you where the pitchers spent time in the field. The reason I chose 1957 as the cutoff was because anyone curious about these guys should be able to look them up on Baseball-Reference, go to their batting gamelogs (available if you scroll down to the batting section of their page), and see exactly when they appeared elsewhere in the field. For example, Randy Johnson's 1993 batting gamelog is here and you can see he spent an inning in left field on October 3. You can even get the box score for the game.
One last thing, does anyone know the John Upham story? As you can see on the list, he's the only pitcher who doesn't have an asterisk next to the number 1, indicating he did not spend over half his games on the mound. He appeared in 21 games in his career, seven times on the mound, twice in the outfield, nine times as a pinch hitter, and three times as a pinch runner. He even spent an entire game in center field in 1968 (box score). He didn't get much time at bat or on the mound for his career, but I thought it was interesting.
Oh, I should also mention it's entirely possible I missed someone because of the clumsy way I looked up the list. If you know I did, drop me a line!
UPDATE: My dad emailed me to tell me about Sam McDowell, a Cleveland lefthander in the 60's and 70's. On July 6, 1970, McDowell was moved to second base during a game for one-third of an inning and then returned to the mound to finish the game. Curiously, he actually recorded a putout, ending the top of the eighth inning. Also, on September 2, 1970, he was moved to first base for two-thirds of an inning until returning to the mound for the rest of the game. Oddly, the team he faced in both games was the Washington Senators, and the pitcher to replace him both times was Dean Chance.