Rudy May played for the Angels when I was a kid.
A contender for longest may be L’N’H’R, (pronounced “L apostrophe N apostrophe H apostrophe R”).
He played one game in 1912 (Ty Cobb was kicked out for beating up a spectator, and the rest of the Tigers sat out the following game in a show of support for him). The owner scraped together a team of amateurs at the last minute, one of whose name appeared in the scorecard as “L’N’H’R”.
A years-later account of the game speculated, “No one knows to this day if his name was Loopenhower or Leninhasinger, and I bet his wife still calls him a liar when he swears he once played for the Detroits”.