Two-time defending champion Matteo Berrettini has pulled out of the Queen's Club Championships, the world number 21 said.

The 2021 Wimbledon runner-up withdrew from the Monte-Carlo Masters, Madrid Open and French Open due to a recurring abdominal injury before returning at the Stuttgart Open, where he suffered a first-round loss to fellow Italian Lorenzo Sonego.

"I'm really sad to have to withdraw from the tournament, and not get the chance to defend my title. I wish the tournament and everyone involved a successful week. I look forward to coming back next year," the 27-year-old said.

The Queen's Club Championships gets underway in London later on Monday.