The Springfield Isotopes are Springfield's only minor league baseball team.
The team is shown as drastically underfunded and struggling in competition. Their home games are played at Duff Stadium as Duff Beer sponsors and co-manages the team. The Isotopes name is most likely in reference to Springfield's nuclear power plant. Homer Simpson was the Isotopes mascot for a brief period, taking over from the Capital City Goofball, before being fired.
The low quality of the team combined with its financial difficulties has prompted management to consider moving the team. After the team was sold to the Duff corporation (from the Mafia, and according to Moe the last of the family-owned teams), Homer once learned that there were plans to move the team to Albuquerque, and staged a hunger strike to prevent it. Springfield become aware of their plans to move the team due to Homer's efforts and their premature roll-out of food packaging with "Albuquerque Isotopes" written on them. Albuquerque decides to change the decision to move the team.
- Episode – "Dancin' Homer"
- Episode – "Lemon of Troy" (Mentioned; hat with logo seen)
- Episode – "Wild Barts Can't Be Broken"
- Episode – "Hungry, Hungry Homer"
- Episode – "The Bart of War" (Mentioned; stadium seen)
- Episode – "Marge and Homer Turn a Couple Play"
- Episode – "The Bob Next Door" (Mentioned)
- Episode – "The Kids Are All Fight" (Name seen on a flag)
- Comic book – It's In The Cards