纳达尔过去便屡传背部问题，这次澳网开打之前承认已为背伤所苦15天，不保证能打澳网。请看本报昨日的报道：

Rafael Nadal admitted Sunday he had been “suffering” for 15 days with a sore back and could not guarantee he’ll play the Australian Open, with the injury threatening to derail his bid for a record 21st Grand Slam.

The world number two sat out Spain’s ATP Cup campaign in warmup week, and he hasn’t played a competitive match since the ATP Finals in London in November.

His only appearance since was an exhibition game against Dominic Thiem in Adelaide nine days ago, where he first experienced stiffness in his back.

“Not great obviously,” he said of the back injury on the eve of the first Grand Slam of the year. “It’s true that for the last 15 days I have been suffering.”

报道中的sit out就是“旁观、不参加”，例如：

To be honest, I’m a little winded, so I think I’ll just sit this game out.

老实说，我觉得有点喘，这场比赛我还是不打了。