Corking a baseball bat in the top level of baseball has gone on since the very beginning of baseball. Every sense the 1900’s there have been some kind of “doctored” bats. At the very beginning players would drive nails into their bats, they did this so they could add more weight to the barrel of the bat. At that time whenever a player was caught with a corked bat they were not suspended or ejected their bat was just removed from the game. Not until the 1975 season was a rule put in place that ejected players who were caught using a doctored bat in a game. The rule states:
“6.06 A batter is out for illegal action when:
(d) He uses or attempts to use a bat that, in the umpire’s judgment, has been altered or tampered with in such a way as to improve the distance factor or cause an unusual reaction on the baseball. This includes bats that are filled, flat-surfaced, nailed, hollowed, grooved or covered with a substance such as paraffin, wax, etc. No advancement on the bases will be allowed and any out or outs made during a play shall stand. In addition to being called out, the player shall be ejected from the game and may be subject to additional penalties as determined by his league president.
Rule 6.06 (d) Comment: A batter shall be deemed to have used or attempted to use an illegal bat if he brings such a bat into the batter’s box”(David Wade