One umpire from each crew will wear a microphone that he can turn on and off during the game at his discretion. The networks said they won't air live audio from the microphones.

"We have put microphones on players, in the dugouts, on the foul poles, and this is just another way to bring fans closer to the game," Fox Sports President Ed Goren said in a telephone interview.

News Corp.'s Fox and Walt Disney Co.'s ESPN asked to put microphones on umpires for several years before getting approval from Major League Baseball and the Umpires Union.

Both networks said they would be selective in the audio they choose to use and umpires can turn off the microphones if a player or manager is arguing a ruling. The networks said they may decide to air contested calls on delay if considered suitable.