Baseball was a team sport that originated on Earth in the 19th century and gained worldwide popularity during the 20th century, becoming a national obsession around the 1940s. (TNG: "The Big Goodbye") During this time professional leagues organized around the sport on several continents. The game continued to be played in the 21st century but its popularity began to decline until 2042, when the final World Series was played and the professional stage of the game came to a close. (DS9: "If Wishes Were Horses")
Despite its wane in popularity, the lexicon and history of the game endured and by the 24th century, the sport had become popular among Humans again for its grace and simple elegance. At this time, the names and achievements of many of its greatest players were still known and cherished by many people including Jack Crusher and Paul Stubbs. Crusher later taught his son, Wesley how to play the game. (TNG: "Evolution") Benjamin Sisko and his son Jake were notable baseball fans; so were Kasidy Yates and her brother on Cestus III, one of the few locations where the sport was still practiced in the 24th century. By the end of the century, the London Kings had signs that advertised their team in Greater Boston. (PIC: "Remembrance")
Commander Sisko used the game of baseball to help the Prophets to understand linear time when he first encountered them. He explained that the reason the game was worthwhile was that corporeal beings like Humans didn't know what the outcome would be. "Every time you throw this ball a hundred different things can happen in the game." (DS9: "Emissary")
Sisko also kept a baseball on his desk in his office aboard Deep Space 9 and encouraged an interest in the game among his senior staff, including accepting a challenge to a game by the crew of the USS T'Kumbra in 2375. (DS9: "Take Me Out to the Holosuite")
In the initial days of the Federation administration of Deep Space 9, Quark believed a knowledge of baseball might be a business opportunity. He therefore made a study of the game, learning some of the names most associated with the sport, such as Tris Speaker, Ted Williams and Buck Bokai. While he did not appear to attain a detailed knowledge of the game, he did assess that the game represented a fundamental shift in the nature of the services he would need to provide to his newest clientèle. For Quark, Sisko's obsession with baseball represented a need to expand into the area of family entertainment – a realization that inspired Quark to attempt to expand his holosuite space. (DS9: "If Wishes Were Horses")
After traveling back in time to 1947, Quark mentioned baseball to General Denning as an example of his knowledge of Human culture. This was a bluff to cover his lack of knowledge. (DS9: "Little Green Men")
- Chapter 25: "The infield fly rule is invoked in instances where, with both first base and second base occupied, or with first, second and third base occupied... [..] And fewer than two out, the batter hits a high fly which in the judgment of the umpire can readily be caught by an infielder or the pitcher or catcher inside fair ground. The batter is then called out regardless of whether the ball is subsequently caught or not. An attempt to bunt, however, under the conditions noted above, which results in a fair fly shall not be regarded an infield fly."
- Rule No. 4.06, Subsection A, Paragraph 4: "No player shall at any time make contact with the umpire in any manner. The prescribed penalty for the violation is immediate ejection from the game."
- See: Athletes
- See also
- Atlanta Braves
- Boston Red Sox
- Cestus Comets
- Chicago Cubs
- Cleveland Indians
- Crenshaw Monarchs
- Gotham City Bats
- London Kings
- Los Angeles Dodgers
- New York Giants
- New York Yankees
- Pike City Pioneers
- San Francisco Giants
- ENT: "Carbon Creek"
- TOS: "I, Mudd"
A baseball cap worn by Nana Visitor in the episode "Starship Down" was sold off on the It's A Wrap! sale and auction on eBay. The cap has interior labels of "American Needle" and "Black Diamond Authentic Series" inside. 
The Pocket TNG novel Fortune's Light attributed the fall of baseball to monetary and labor issues, while the Pocket DS9 novel The 34th Rule also partially blamed the death of A. Bartlett Giamatti (β).