The overnight rating for Fox was 0.56, or 790,000 homes, for the 5-hour show. The John Deere Classic (3 hours) on CBS drew a 1.11 rating, or 1.67 million homes, according to Nielsen. That's not great either, but decent enough in the post-Woods era on a week before a major.
When you have five or fewer Americans in the top 20 at the start of the show, and the Olympic rings aren't on display, there will be a tune-out on an American network, no matter how interesting the golf. Or any other sport.