A stiff and sore Tiger Woods admits playing three US PGA Tour events in a row is cause for concern after a fresh injury scare surfaced on the eve of the FedEx Cup playoffs.
Woods - who has played just four tournaments since winning his 15th major at the Masters in April - was unable make a full swing on the back nine of his Wednesday pro-am at the Northern Trust in New Jersey.
The Northern Trust kicks off the PGA Tour's finals series which are staged in succession for the next three weeks.
The 43-year-old, who underwent spinal fusion surgery in 2017, winced in pain on the front nine of his pro-am and was only able to chip and putt for the back nine at Liberty National golf course.
Afterwards, the 81-time PGA Tour winner tried to downplay his ailing back.
"I was getting stiff and it's best to be smart about it," Woods said on Wednesday at the Northern Trust.
"It's kind of what I did pre-Augusta when I went out there and just chipped and putted for nine holes."
Woods has only once played back-to-back weeks on the PGA Tour this year and has not played three in a row since September last year.
Asked about the prospects of playing three weeks in a row, Woods added: "There is concern because given hopefully the pressures I'm going to be facing, hopefully putting myself in contention, that's why it gets difficult."
In the four events he has managed since April's Masters, Woods has missed the cut twice and both were majors (US PGA Championship and British Open).
"I learned a lot last year by playing too much," Woods said of his lean 2019 schedule.
"I pushed it pretty hard and vowed I'd never do that again. I've cut back the schedule quite a bit.
"I can't practice as much as I'd like, certainly can't even sniff how much I used to practice.
"This is kind of how it is. Some days I'm stiffer than others. Yesterday (Tuesday) I was out there hitting it great but today I'm stiff. Hopefully I'm not that way tomorrow."
Four-time major winner Rory McIlroy admitted each piece of injury news raised concerns about Woods' health.
"I think everyone does (worry)," McIlroy said.
"Golf is better when Tiger is around; hopefully he can still compete a handful of times a year.
"But he's Tiger Woods. He doesn't need to prove anything to anyone.
"He can put the clubs away tomorrow and live happily ever after, but he wants to compete."
Woods sits 28th on the FedEx Cup points race and will need to remain within the top 30 to qualify for the season-ending Tour Championship, which he won last year.
But the top 125 points earns who qualified for the Northern Trust will be cut to 70, who advance to next week's BMW Championship, after which the top 30 will be decided.