Defending US Open champion Dominic Thiem will miss this year's tournament with a wrist injury that will rule him out until 2022.

The 27-year-old suffered the setback at the Mallorca Open in June and also withdrew from Wimbledon and the Tokyo Olympics.

World number six Thiem won his maiden grand slam at Flushing Meadows last year with victory over Alexander Zverev in a five-set thriller, but he will not get the chance to defend his title in New York.

"Having spent a week training on court, I still felt pain in my wrist and I knew that it was not 100 per cent," Thiem posted in a statement on his Twitter page on Wednesday.

"I went to see my doctors again and we have decided to follow a conservative treatment, giving the injury more time to recover.

"I'm very disappointed not to be able to defend my US Open title and to miss the rest of the season.

"But I know this is what I have to do. I have a long career ahead of me, so I will only come back once I'm fully recovered and in good shape to compete."

Thiem has a record of nine wins and nine losses this season, with his best result coming at the Madrid Open in May when reaching the semi-finals.

Twenty-time grand slam winner Roger Federer last week pulled out of the US Open, which runs from August 30 until September 12, after undergoing knee surgery.