The 43-year-old, who came back from spinal fusion surgery in 2017, looked a shadow of the player who won the Masters in April as he carded a first-round 75 at Liberty National Thursday.
Continuing where he left off after missing the cut at the British Open, Woods appeared stiff and out of sorts and withdrew with a side strain ahead of the second round in New Jersey.
“I went for treatment early Friday morning, but unfortunately I’m still unable to compete,” he said in a statement.
“I’d like to thank the New Jersey and New York fans for their support and remain hopeful I can compete next week at the BMW Championship.”
READ: Woods admits back still a problem and yearns for ‘hot weeks’
‘Things are different’
Woods cut short his pro-am practice round Wednesday, and said of his back after his ending four over Thursday: “It’s a little bit stiff, yeah, but that’s just the way it’s going to be.”
He added of his game: “It was just off. I was just trying to feel it, trying to find it, and then could never get it.”
Woods has played only four tournaments since winning that remarkable 15th major title, and first in 11 years, at Augusta.
The former world No.1 missed the cut in the PGA Championship, tied ninth at the Memorial tournament, was tied 21st in the US Open and failed to make the weekend at the Open.
At Royal Portrush, his verdict on another disappointing display was that his ailing body — after four major back surgeries — was still a hindrance and would only allow him to practice and perform intermittently.
“Things are different. I’m going to have my hot weeks, I’m going to be there in contention with the chance to win and I will win tournaments, but there are times when I’m just not going to be there and that wasn’t the case 20-something odd years ago when I had a different body and I was able to be a bit more consistent,” he told reporters.
The Northern Trust is the first of the three Fed Ex Cup playoff events, culminating in the Tour Championship, which Woods won last year for his first title since 2013 after making an impressive recovery from long-term back problems.
READ: Woods’ Masters win has Nicklaus ‘shaking in my boots’
Woods is just four major titles adrift of Jack Nicklaus’ record and one win behind Sam Snead’s mark of 82 PGA Tour victories.