The new track sounds like an anthem for the Red and Gold - It's called "Niner Gang."
The team even tweeted a link to the song and said, "New slap for your tailgate today," ahead of the Monday night game against Seattle.
E40's loyalty to Bay Area sports teams is well documented.
His song "Choices (Yup)" blew up as a fan favorite when it was remixed to sound like a theme song for the Golden State Warriors.