British number one Jack Draper has pulled out of this week’s Shanghai Masters through injury.

The 22-year-old retired from his quarter-final clash against France’s Ugo Humbert at the Japan Open on Sunday.

Draper required treatment on an abdominal problem and, after trying to continue, had to call it a day at 7-5 2-1 down.

Draper’s camp say he does not yet know the extent of the injury but feels the turnaround from Tokyo to Shanghai is too quick.

The Japan Open was Draper’s first ATP tournament since he reached the semi-finals of the US Open earlier this month.

The world number 20 played for Great Britain in the Davis Cup a few days later but lost both of his matches.

Afterwards, Draper complained that the current tennis schedule is too busy.

“It’s a mental calendar,” he said. “There’s literally no break. It’s really mentally and physically challenging.”

Draper had a first-round bye in Shanghai and would have faced either Hugo Gaston or Jaume Munar in round two.

Novak Djokovic, Carlos Alcaraz and world number one Jannik Sinner are in the draw.