MLB Players Across the League Are Wearing Number 4 to Honor a Legend of the Game

Sports uniforms are often used to honor one thing or another, and those gestures are often a nice reminder that the players care about things other than the results of that particular game. When players across the league are all wearing the same thing, though, some people naturally wonder what the reason might be.

At the beginning of June, players across the MLB were seen sporting the number 4. The fact that the gesture was so widespread naturally made people curious about what it was honoring. Here's what we know.

MLB players wear number 4 in June as part of Lou Gehrig Day, a celebration of the legendary Yankee player who played in 2,130 consecutive games. June 1, 2025, marked the 100th anniversary of the first game in that streak, and the players wearing his number is just one way that the league plans to honor him in the coming weeks. The celebration is also designed to raise awareness of ALS, a disease that he was diagnosed with and that has become synonymous with him.

Lou Gehrig Day was first instituted in 2021 and has been celebrated by the MLB every year since.

“MLB’s efforts will raise awareness and funds for ALS research and highlight the work of the groups and individuals who are pursuing cures,” according to the league. “The league also will remember the legacy of Gehrig and people who have been lost to the disease which bears his name.”

If you haven't heard of Gehrig, he was one of the players on the legendary Yankees team dubbed "Murderers' Row." He was first signed by the team in 1923 and wore No. 4 throughout his career. He was inducted into the Hall of Fame in 1939, which is also the year he retired from baseball following his ALS diagnosis. He died at the age of 37 in 1941, just two years after his retirement.

The disease he was diagnosed with and helped make famous still has no cure, and involves the gradual weakening of various muscles throughout the body. Although people who are diagnosed today tend to live longer than Gehrig did more than 80 years ago, the disease remains one that requires more time and research.

Gehrig never missed a game and played on some of the greatest teams in the history of the sport. Given the tragic nature of his death and the accounts of his gentle, good nature, Gehrig has understandably been remembered fondly by generations of baseball fans.

Although we don't know how long the MLB plans to celebrate Lou Gehrig Day, it doesn't seem like they plan to stop anytime soon. Frankly, it's a little strange that they waited this long to start. Given how much he meant for the sport and how much his legacy continues to impact those around him, it seems like the least the MLB can do.