In baseball, a corked bat is a specially modified baseball bat that has been filled with cork or other lighter, less dense substances to make the bat lighter without losing much power. A lighter bat gives a hitter a quicker swing and may improve the hitter's timing. In Major League Baseball, modifying a bat with foreign substances and using it in play is illegal and subject to ejection and further punishment.
To cork a bat, a hole approximately 1/2-inch (12.5 mm) in diameter is drilled down through the thick end of the bat roughly six inches deep. Crushed cork, bouncy ball, sawdust, or other similar material is compacted into the hole and the end is typically patched up with glue and sawdust. However, this weakens the bat's structural integrity and makes it more susceptible to breakage, even more so if the cork is placed beyond roughly six inches into the bat. Corked bats are typically discovered when they break during play.
Using a corked bat in Major League Baseball is in violation of Rule 6.06 (d), which reads in full:
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 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 Punishment advisor.
Since 1970, six players have been caught using corked bats. The following table summarizes these events:
|Sammy Sosa||Chicago Cubs||June 3, 2003||Eight games||Corked bat||Bat was meant to only be used in batting practice|
|Wilton Guerrero||Los Angeles Dodgers||June 1, 1997||Eight games||Corked bat||None|
|Chris Sabo||Cincinnati Reds||July 29, 1996||Seven games; Reds fined $25,000||Rubber balls in bat||Borrowed bat from unnamed teammate|
|Albert Belle||Cleveland Indians||July 15, 1994||Seven games||Corked bat||None|
|Billy Hatcher||Houston Astros||August 31, 1987||Ten days||Corked bat||Borrowed bat from pitcher Dave Smith|
|Graig Nettles||New York Yankees||September 7, 1974||Ten days||Six super balls in bat||Received bat as a gift from a fan|
According to the MythBusters August 8, 2007 baseball special, a ball hit by a corked bat travels at only half the speed of a ball hit by an unmodified bat, causing it to go a shorter distance. Additionally, the cork inside the bat actually absorbs the kinetic energy like a sponge, hindering the batter's performance. In addition, because corked bats are lighter, they have less momentum to transfer to the ball. This led to the conclusion that the use of a corked bat had fewer benefits over a regular bat. The show also notes that while filling a bat with cork makes it lighter, there is nothing in the rule book that prevents a player from simply using a lighter, uncorked bat. However, lighter wood bats are shorter than heavier bats (a baseball bat has a linear weight-to-length ratio referred to as "drop"); drilling out a heavier bat and adding a less dense filling allows the swing speed of a lighter bat with the plate reach of a heavier one, which may allow the batter to make solid contact with pitches more effectively.
- "MLB Official Rules, Section 6", MLB.com (accessed June 8, 2006)
- "Corked bat-related penalty reduced by one game", ESPN.com news services, June 11, 2003 (accessed March 6, 2009)
- "Sosa gets eight games, appeals", MLB.com (accessed June 28, 2006)
- "MythBusters Baseball Special". MythBusters. Season 6. Episode 83. 2007-08-08.