Hi,
You might like to search the internet for various comments on this. eg http://www.phrases.org.uk/bulletin_board/16/messages/591.html, which discusses the apparent connection with baseball.
Clive
WAY OUT IN LEFT FIELD - Out of touch, eccentric, odd; also, misguided. This term alludes to the left field of baseball, and there is some disagreement concerning its origin. Some writers suggest it comes from the remoteness of left field, but only in very asymmetrical ballparks is left field more distant than right field. Others suggest it alludes to the 'wrongness' of left as opposed to the 'rightness' of right. A correspondent of William Safire's in the "New York Times" said it was an insulting remark made to those who bought left-field seats in New York's Yankee Stadium during the years that Babe Ruth played right field, putting them far away from this outstanding player. Perhaps the most likely theory is that it alludes to inmates of the Neuropsychiatric Institute, a mental hospital, which was located behind left field in Chicago's old West Side Park. Hence being told you are 'out in left field' would mean you were accused of being as peculiar as a mental patient. In any event, the term has been used figuratively for various kinds of eccentricity and misguidedness since the first half of the 20th century. John Ciardi also cited a synonym, 'out in left pickle,' maintaining that 'pickle' was baseball slang for the outfield. Perhaps it once was, but it is no longer current." "Southpaws & Sunday Punches and other Sporting Expressions" by Christine Ammer (Penguin Books, New York, 1993).