WATFORD, United Kingdom (AFP) - Reigning US Masters champion Danny Willett withdrew from the British Masters with a back injury shortly before he was due to tee-off in Thursday's (Oct 13) first round.

Willett, 29 was due to tee-up at The Grove Club near Watford, north of London, alongside fellow Englishman Andrew "Beef" Johnston and in-form Swede Alex Noren.

A European Tour official indicated Willett had complained of back problems during Wednesday's Pro-Am.

Willett's withdrawal led to South African Justin Walters, as first reserve, making his way into the £3 million (S$5 million) event and taking the place of the Augusta National winning hero.

Willett returned to solo competition at last week's Alfred Dunhill Links Championship following an indifferent European Team effort on debut a week earlier in the team's Ryder Cup loss away to the United States.

But the current World No. 9 struggled in Scotland and missed the cut.

Willett's only bright note last week was teaming with Masters winning caddy, Jonathan Smart to win the pro/amateur team event.

Willett's withdrawal from the British Masters also robs the event of its highest world ranked player with Noren, currently ranked 26th, now filling that role.

And Willett's exit came after fellow England golfer Justin Rose withdrew just prior to the event, citing an on-going back injury he first suffered earlier this year in the PGA Tour's Players Championship.