(Chicago Defender, June 17, 1933, p. 8)
The Cleveland Giants were a local independent club that played in the Cleveland Colored Baseball League, but they were taken over by more ambitious ownership in July, and in August joined the Negro National League. The roster was overhauled; in a deal brokered by league president Gus Greenlee, players from the defunct Akron and Columbus clubs were added to the Giants. So Baxter didn’t play in any Negro league games (like Toni Stone, Connie Morgan, and Mamie Johnson would in the 1950s), but she did play for a team that would soon join the Negro leagues.
Isabelle Baxter is mentioned in Harold Seymour’s The People’s Game and in several other sources, so she’s not new to historians. I haven’t been able to find out anything for sure about her. There was an Isabelle Baxter living in Cincinnati in the 1930 census, aged 15 (which would have made her 18 when she played for the Giants), living with her parents, William and Florence Baxter, and siblings Julie, Walter, William Jr., and Bettie J. Baxter. But of course that’s not a certain ID.