I recognize The Shipping News.
"To come out of leftfield" means to say something unexpected.
It is a baseball expression.
- left field, as in "that insult really came out of left field" -- Unusual, unexpected, or irrational. AHDI dates this idiom back to the mid-1900s; it also states that the precise allusion is disputed, but a number of theories exist. Rumored to originally describe fans who came to Yankee Stadium to see Babe Ruth (a right fielder) but who bought tickets for the wrong side of the field. Another legend is that the phrase originates from Chicago's old West Side Park which had a mental hospital located behind left field. Visiting players came to refer to something as odd to be 'out in left field.' The flaw in that story is that Cook County Hospital was behind third base, not left field.