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.

After reviewing videos of clubhouse attendants from around the league, officials found a wide variety of muddying techniques.

The proper technique involves "painting" the full surface of the ball with mud using two fingertips. Then comes a very precise rubbing motion with the ball in between both hands to get mud into the pores of the leather. Muddying each ball is a 30- to 40-second process.

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.

The move comes after the league garnered feedback from players over the past two months and is not in response to the latest on-field incident after Angels pitcher Michael Lorenzen hit Seattle Mariners outfielder Justin Upton in the head with a pitch Friday. Lorenzen indicated that the ball slipped out of his hands. The decision to use a uniform muddying technique has been in the works for weeks.

In addition to the specific technique required to muddy baseballs, the memo informs teams of standardized handling and storage of the balls:

• All baseballs to be used in a specific game must be mudded within 3 hours of all other baseballs being used in that game.

• Once the muddying process is completed, all balls should be placed back in the Rawlings boxes with dividers, and the boxes should then be placed in the humidor. In the past, balls were allowed to go directly into the humidor.

• When taken out of the humidor for that day's game, only eight dozen balls at a time should be placed in a ball bag. In the past, there was no limit to how many balls could be in the bag but players felt the ones at the bottom felt too "chalky." Additionally, the inside of the ball bags will be required to be cleaned thoroughly by wiping with a damp cloth and then with a dry cloth to make sure there is no excess residue, dust or moisture.

• Each team will be provided a poster showing the acceptable range of appearance for a mudded baseball. (dark/light)

• All game balls must be stored in humidors for a minimum of 14 days before being taken through the muddying process.

The league admits there's no perfect solution to every ball having the same feel but hopes the standardized handling and storage of them will be a successful attempt to "improve the consistency within the baseballs," according to a league source.

The updated guidelines will go into effect Wednesday after Michael Hill, senior vice president of on-field operations, speaks with each of the 30 teams.