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.

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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.

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