Four-time Masters champion Tiger Woods has been forced to pull out of this year's tournament at Augusta due to back problems.

The 40-year-old has been out of action since August and said in a statement that he would not be able to compete next week.

"After assessing the present condition of my back, and consulting with my medical team, I've decided it's prudent to miss this year's Masters," said Woods.

"I've been hitting balls and training daily, but I'm not physically ready. I've said all along that this time I need to be cautious and do what's best for my long-term health and career.

"Unfortunately, playing Augusta next week wouldn't be the right decision. I'm absolutely making progress, and I'm really happy with how far I've come, but I still have no timetable to return to competitive golf."

Woods, who won the green jacket in 1997, 2001, 2002 and 2005, has now missed the tournament in two of the last three years. He finished tied-17th last year.