Why are MLB teams wearing a number 4 patch on their jerseys today?

Major League Baseball is marking Lou Gehrig Day this Sunday, June 1, 2025, an annual league-wide event held to honour Gehrig’s legacy and raise awareness for ALS, the disease that ended his life and ultimately took on his name.

To recognize the occasion, all 30 MLB teams will wear a number “4” patch on the front of their uniforms, the number famously worn by Gehrig during his Hall of Fame career with the New York Yankees. The patch uses the Yankees’ familiar uniform typeface and navy blue colouring and is placed on the upper left chest of each jersey.

LINK: Lou Gehrig’s baseball career in logos and uniforms

Several ballparks will display a glowing “4” in their press boxes, and pre-game ceremonies across the league will feature video tributes and ALS-related community outreach efforts. The event has been held annually for several seasons on or around June 2, the anniversary of Gehrig’s death from ALS in 1941.

Gehrig played 17 seasons with the Yankees from 1923 to 1939, earning two MVP awards, a Triple Crown, and being named a seven-time All-Star. His record of 2,130 consecutive games played stood as the MLB mark for more than half a century and was once thought to be baseball’s unbreakable record; it was finally surpassed by Cal Ripken, Jr. in 1995.