Two animal baseball teams, The Foxes and The Rabbits, battle it out on the field for supremacy. Eventually, the star hitter for The Foxes finds himself up at bat and the final hope for his team's victory. However, he finds himself distracted by a lovely female fox cheering for him from the bleachers and he takes his eye off the last ball.
 
Produced as a short film in September 1949 by Kindaieigasha Co.,Ltd., "Kitsune no Homerun-O" (Fox, The Home Run King) was directed by Satoshi Morino with animation by Kazue Saku And Terada Noboru.
 
In 1957, it was imported by East-West TV Inc. and dubbed into English (using one voice as a narrator, but retaining the original Japanese voices for the animal characters) and released as "Seventh Inning Stretch" by Medallion TV for syndication in the US. 
 
(Source: AniDB)