Doubts are mounting about Tiger Woods’ chances of playing next month’s Masters after he withdrew from this week’s Arnold Palmer Invitational.

World No.1 Woods has been struggling for weeks with back spasms and pain and he reluctantly acknowledged he could not defend the Arnold Palmer Invitational title which he has won eight times.

“It’s too early to know about the Masters and I will continue to be evaluated and work closely with my doctors,” Woods said on his website.

“Unfortunately, my back spasms and the pain haven’t subsided. I personally called Arnold today to tell him that, sadly, I won’t be able to play in his tournament this year.

Woods is running short of time to be fit and firing for the Masters at Augusta National from April 10-13.

A14-time major champion chasing the all-time record of 18 won by Jack Nicklaus, 38-year-old Woods has not won a major since the 2008 US Open.

His injury woes are mounting and he withdrew during the final round of the Honda Classic three weeks ago because of the back problem and has made just four starts this season.

His best finish is a tie for 25th place at the WGC-Cadillac Championship two weeks ago.

Woods failed to make the secondary cut at the Farmers Insurance Open and tied for 41st at the Dubai Desert Classic.

Woods claimed a second consecutive Arnold Palmer title last year, becoming only the second player to win the same tournament eight times after Sam Snead, who won eight Greater Greensboro Open titles.