They call Cal Raleigh “The Big Dumper” because of his big backside, and the nickname stuck once teammates and fans picked up on it.

Origin of the nickname

  • The nickname started in the Seattle Mariners clubhouse around 2020, when teammate Jarred Kelenic began calling him “Big Dumper.”
  • Kelenic later used it publicly on social media when Raleigh was promoted to the big leagues, which helped the name go viral among Mariners fans.

What it actually refers to

  • Raleigh has confirmed in interviews that “Big Dumper” literally refers to his large butt, joking that he has “always had a large butt” and calling it “a blessing and a curse.”
  • Broadcasters and writers now openly associate the nickname with his “pretty large posterior,” which has become part of his on-field persona.

How fans and media use it now

  • The nickname has turned into a fan favorite, showing up on signs, broadcasts, and social media whenever he hits big home runs or makes big plays.
  • Even as some family members (like his mom) are not huge fans of the name, it has become a defining, light‑hearted part of his public image in MLB.

TL;DR: Cal Raleigh is called “The Big Dumper” because teammates started joking about his big butt, he leaned into the joke, and it became his iconic, very literal nickname.

Information gathered from public forums or data available on the internet and portrayed here.