Left field

If something comes out of left field, is out in left field, or comes from left field, it means odd, bizarre or unexpected. The origin is generally acknowledged as deriving from the left field of baseball, and is therefore an American expression, first attested from c.1940. The exact origin, however, as it relates to baseball is obscure and very much disputed. The most favoured explanation is that fielders who are on the left of the baseball diamond are generally the furthest out, because that is where right-handed batters generally tend to hit the ball. Quite why this should be interpreted as odd, bizarre or unexpected, remains a mystery. If left field is where right-handed batters tend to hit the ball, one would have thought it should mean the complete opposite. Another theory is that because most balls are hit into left field, a fast, unexpected throw from there to home or first base can often surprise a runner. However, the jury is still out as to how or why out of left field is odd, bizarre or unexpected.