Piersall was one of the earliest recorded cases of bipolar disorder in Major League Baseball, although at the time, the disorder was not known by that name.
"On May 24, 1952, just before the game against the New York Yankees, Piersall engaged in a fistfight with Yankee infielder Billy Martin. Following the brawl, Piersall briefly scuffled with teammate Mickey McDermott in the Red Sox clubhouse.
"After several such incidents, Piersall was sent to the minor league Birmingham Barons on June 28. The final straw came when Piersall spanked the four-year-old son of teammate Vern Stephens in the Red Sox clubhouse during a game.
In less than three weeks with the Barons, Piersall was ejected on four occasions, the last coming after striking out in the second inning on July 16. Prior to his at-bat, he had acknowledged teammate Milt Bolling's home run by spraying a water pistol on home plate. Piersall then moved to the grandstand roof to heckle home plate umpire Neil Strocchia.
Receiving a three-day suspension, Piersall entered treatment three days later at the Westborough State Hospital in Massachusetts. Diagnosed with "nervous exhaustion," he would spend the next seven weeks in the facility and miss the remainder of the season.
According to his autobiography, Piersall blamed much of his condition on his father, who pressured him as a small child to aim for success as a professional baseball player.
Piersall returned to the Red Sox in the 1953 season, finishing ninth in voting for the MVP Award, and remained a fixture in the starting lineup through 1958.
He once stepped up to bat wearing a Beatles wig and playing "air guitar" on his bat, led cheers for himself in the outfield during breaks in play, and "talked" to Babe Ruth behind the center field monuments at Yankee Stadium.
In his autobiography, Piersall commented, "Probably the best thing that ever happened to me was going nuts. Who ever heard of Jimmy Piersall, until that happened?"'