Though professional baseball was allowed to continue and spring training did take place throughout World War II, teams were required to train much closer to their home cities instead of traveling south. These travel restrictions allowed the railway system to be used for transporting soldiers and supplies around the country.

As a result, teams that ordinarily carried out their spring training in Florida instead trained in cities east of the Mississippi River and north of the Ohio River. For example, the Boston Red Sox did most of their wartime spring training in Medford, Mass, while the Chicago White Sox trained in Indiana.