World number one Dustin Johnson has pulled out of a tournament with injury just a week before the PGA Championship

• Dustin Johnson has pulled out of this week's AT&T Byron Nelson tournament with a knee injury.
• The world number one's withdrawal comes just a week before the US PGA Championship.
• "I am not pleased about this situation," said Johnson.

World number one Dustin Johnson has withdrawn from this week's AT&T Byron Nelson tournament with a knee injury - just a week before the US PGA Championship.

The 36-year-old, who had knee surgery in 2019, said in a statement: "It is with deepest regret that I must withdraw from this week's AT&T Byron Nelson.

"Unfortunately, the knee discomfort I occasionally experience has returned and, after consultation with my team and trainers, I feel it is best that I remain at home and focus on my rehabilitation work."

The American has been replaced by Australia's Greg Chalmers in the Byron Nelson field, which features a number of the world's top golfers including Jordan Spieth, Bryson DeChambeau, Sergio Garcia, and Masters winner Hideki Matsuyama.

"I am not pleased about this situation," added Johnson. "I was really looking forward to playing this week."

Johnson has won 24 PGA Tour titles and two majors, most recently the 2020 Masters in November. He also finished as tied runner up at last year's PGA Championship behind Collin Morikawa.

The US PGA, the second men's major of the year, begins at Kiawah Island's Ocean Course in South Carolina, Johnson's home state, on May 20.

It is not yet known whether Johnson will be fit to play.