Major League Baseball is now requiring teams to "muddy" baseballs before games using the exact same technique, according to a league memo sent to all 30 teams on Tuesday and obtained by ESPN.

Muddying is the process of removing gloss from new baseballs to give pitchers a better grip. It's been used in the game for decades and is as important as ever considering the league's crackdown on the use of foreign substances over the past 12 months.

In past years, muddying involved clubhouse attendants preparing baseballs by rubbing Delaware River mud -- which comes in a can -- days before each game. Moving forward, they'll be required to continue to muddy balls on game day only and all with the same technique.

600 ESPN El Paso logo
Get our free mobile app

The league memo is another attempt to reach as much uniformity as possible for the dozens of balls used throughout major league parks every night.

LOOK: MLB history from the year you were born

Stacker compiled key moments from Major League Baseball's history over the past 100 years. Using a variety of sources from Major League Baseball (MLB) record books, the Baseball Hall of Fame, and audio and video from events, we've listed the iconic moments that shaped a sport and a nation. Read through to find out what happened in MLB history the year you were born.

More From 600 ESPN El Paso