McEwan, whose On Chesil Beach is among the 13 novels published over the past 12 months to be "long-listed" for the award, says it is a "wholly arbitrary matter if your number comes up or not and depends entirely on getting the right jury in the right year".
The winner of the 1998 award for his novel Amsterdam - generally agreed by critics not to be one of his greatest works - adds, for good measure, that he wished the judges would announce the winner at the start of the annual awards dinner.
"That way the winner and the runners-up, all dressed up in their penguin suits or dresses, at least have a chance of enjoying themselves."
McEwan, who is attending the Edinburgh International Book Festival, will scarcely have done himself any favours with the judges of this year's award, who will announce the winner at a dinner at Guildhall in London on October 16.
McEwan, who will learn next week if he has made the shortlist, has had a long and complicated relationship with the award. He was disappointed when Atonement - often regarded as his most accomplished work - failed to win in 2001 after being a shortlist favourite and Saturday was snubbed in 2005 even though it was lauded by the critics.
Even his inclusion this year isn't without controversy, as many think that On Chesil Beach is too short to be considered a novel. Set in 1962, it tells the story of Edward and Florence who, on their wedding night, are both suppressing anxieties about their immediate and long-term future.