Why Do They Rub Mud on Baseballs? MLB’s Secret Mud Explained

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Every baseball used in a Major League game is rubbed with a special mud before first pitch to take the slick factory gloss off the cowhide and give pitchers a better grip. The mud, sold as Lena Blackburne Baseball Rubbing Mud, comes from a secret spot along a tributary of the Delaware River in New Jersey and has been used in the majors since the late 1930s.

Equipment explained
Baseball rubbing mud at a glance
Why every MLB ball is muddy
Why
New balls are slick; mud dulls the gloss for grip
The mud
Lena Blackburne Baseball Rubbing MudNamed for the coach who found it
Where it comes from
A secret location near the Delaware River in New Jersey
Used since
The late 1930s
Who rubs it
Umpire room attendants and clubhouse staffBefore every game
How many balls
Around ten dozen per game
Rules
MLB set standard rubbing and storage procedures in recent seasonsTo make balls more consistent from park to park

Before and After

New ball Rubbed ball
Surface Shiny and slick Dull and slightly tacky
Color Bright white Light tan
Grip Hard to control Easier to spin and command
Consistency Varies by batch More uniform once prepped properly

Why Not Something Else?

MLB has tested pre tacked balls and synthetic alternatives, but the mud has stuck around for generations because nothing else has matched its fine, smooth texture. Grip matters more than ever since the league banned sticky foreign substances in 2021. For what is under the mud, see what baseballs are made of.

Related

How much does a baseball weigh · How many stitches on a baseball · What are baseballs made of · How many baseballs are used in a game

Background from MLB.com.