Marcenia Lyle "Toni" Stone (July 17, 1921 - November 2, 1996) was the first woman to play professional baseball for a previously all-men's major-league team—in the former Negro Leagues. The 5'7" right hander was born in Bluefield, Mercer County, to Boykin and Willa Maynard Stone. Her father was a World War I vet and graduate of Tuskegee University, and her mother was a hairdresser. In 1931, the family moved to St. Paul, Minnesota.

Stone first played for the semi-pro Twin Cities Colored Giants in St. Paul (1947) and then later for the San Francisco Sea Lions (1949) and New Orleans Creoles (1949-53)—the latter two being part of the Negro Leagues' minor league system.

By the early 1950s, the Negro American League—the last remaining Negro Major League—had lost much of its top talent to Major League Baseball, which had begun integrating in 1947 when Jackie Robinson broke Major League Baseball's color barrier. In the years that followed, Major League teams depleted much of the Negro American League's best talent. Desperate to fill empty positions and address the problem of dwindling crowds, the Indianapolis Clowns of the Negro American League signed Stone in 1953 to replace its former second baseman, Hank Aaron, who had joined the National League's Milwaukee Braves. Stone protested the existing protocol demanding that women players wear skirts and was allowed to don a full regulation uniform. While critics felt that Stone's signing was a mere publicity stunt, Aaron recalled that she was a "very good baseball player," and Chicago Cubs great Ernie Banks described her playing style as "smooth."

The Miami Times, while implying that Stone's signing was a gimmick to sell tickets, still asserted, "She gives not an inch of ground as she executes double plays with the finesse of a Jackie Robinson. She's agile, has good baseball instinct, and knows what a Louisville Slugger is for. Her timely batting has amazed baseball experts from coast to coast."

At one point during her 50 games with the Clowns in 1953, Stone was batting .364, fourth highest in the league. Though record-keeping in the Negro Leagues was historically spotty, Stone achieved a respectable career average of .243. With the Clowns in 1953, she supposedly got a single off 47-year-old Satchel Paige, considered by many to be the greatest pitcher ever, although some baseball historians have questioned whether this truly occurred. All the while, she faced sexism from other players and particularly from her manager, Buster Haywood. Some players made sexual advances toward her, and others intentionally tried to get her injured during games. She refused, though, to back down in this male-dominated sport. As she later recounted, ""I'd get right in an umpire's face and let him have it." In 1953, the Jackson (Mississippi) Advocate wrote that "Toni Stone is capable of holding her own against the strongest male opponents and readily admits that none of her opposition takes it any easier on her because of her sex."

After the 1953 season, the Clowns sold her contract to the Kansas City Monarchs, where she played one more year before retiring. She was the first of at least a dozen women to play in the Negro Leagues. In 1993, she was inducted into the International Women's Sports Hall of Fame. She died in 1996 at age 85. That same year, an off-Broadway play about her life (written by acclaimed playwright Lydia R. Diamond) was produced, and in 2022, Google honored her with one of its daily "Doodles" as part of Black History Month.