has any baseball player ever died on the field
Chapman was hit in the head by a pitch thrown by Yankees pitcher Carl Mays, and died 12 hours later. He remains the only Major League Baseball player to have died from an injury received during an MLB game. His death led to Major League Baseball establishing a rule requiring umpires to replace the ball whenever it became dirty, and it was partially the reason--along with sanitary concerns--that the spitball was banned after the 1920 season. Chapman's death was also one of the examples used to emphasize the need for wearing batting helmets (although the rule was not adopted until over 30 years later).
Ray Chapman