On April 20, 1941, the Brooklyn Dodgers become the first major league team to wear protective headgear. Each playerās cap features a special plastic lining designed to fend off the effects of ābeanballs.ā It is a cautious response to the numerous beanball wars ofĀ 1940Ā that hospitalizedĀ Joe MedwickĀ andĀ Billy Jurges, among others. The liners in the caps are thin enough to be hardly noticeable, but most major league players disdain the protection.