more fun history:
The real fun didn’t start until the second game, as left-handers Woodie Fryman and Larry Gura (in perhaps his lone highlight as a member of the Yankees; boy, Billy Martin hated him) engaged in a compelling pitchers’ duel. With the game scoreless in the bottom of the second, Nettles stepped to the plate against Fryman, who was usually brutal against left-handed hitters. On this occasion, Nettles found his way against Fryman, connecting on a home run. Once again, the bat did not break, and the Tigers expressed no suspicion that Nettles had done anything to alter or doctor the bat.
Well, those suspicions finally began to bubble during Nettles’ next at-bat, which came in the bottom of the fifth inning. Nettles took a swing and nicked one of Fryman's pitches with the end of his bat, blooping a single into the outfield. While Nettles stood at first, thinking he had picked up his second hit of the game, he also realized that something was wrong. At the moment of contact with the ball, the top of his bat had come flying off the barrel, which was an unusual way for a bat to break into two pieces. Bill Freehan, the Tigers’ longtime catcher, also noticed something out of place, specifically with the larger piece of discarded wood that lay near home plate. Freehan recognized that the inside of the stained brown bat contained a foreign substance, a fact to which he alerted home plate umpire Lou DiMuro. After inspecting the bat, DiMuro called Nettles out for using an illegal bat.
Curiously, some of the newspaper reports of the day (including one in the New York Times) claimed that Freehan and DiMuro had found cork in the bat, but it was actually small pieces of rubber Super Balls that had been inserted into the center of the bat, which had been hollowed out with a drill. (There's an urban legend that entire balls came bouncing out of the bat, but that is sadly untrue.) Although cork has always been the illegal substance of choice when it comes to filling a bat, any substance other than wood qualifies as illegal, making Nettles a clear-cut "criminal" in this case.