Playing partner Rickie Fowler admitted it was "tough to see" former world number one Tiger Woods withdraw after just 11 holes of his first round at the Farmers Insurance Open with back pain.
The 14-time major winner was playing just his second event of the year on Thursday, and his first round since he shot a career-worst 82 at last week's Waste Management Phoenix Open.
Following that sorry round, Woods insisted his poor play had nothing to do with long-standing back problems and cited adjusting to new swing methods as the root of the problem.
But the 39-year-old, who played just seven events last season after having surgery on a pinched nerve in his back, clearly aggravated the problem and must surely now be a doubt for the Masters which begins on April 9.
"Obviously (it is) tough to see him struggle with getting off to a tough start and it seemed like stuff started to bother him," said Fowler.
"I'm not sure exactly what it was, but obviously I enjoy playing with him and it's just tough not seeing him have his best whether it's with his game or with his health."
Fowler added: "I dealt with some back issues and a lot of guys have dealt with injuries out here. It's hard to play when anything's hurting.
"I'm not sure exactly what it was that was bothering him, I'm assuming it was back-related, other stuff, but yeah, golf may not be an impact or contact sport but the body takes a beating."
Woods claimed after his aborted round that the delays caused by fog in California were mainly to blame for his problems as he could not keep as active as he would have liked.
"When we had that break I never loosened back up again and then when we went back out it got progressively tighter," Woods said.
"It's frustrating that it started shutting down like that. I was ready to go. I had a good warm-up session and then we stood out here getting cold and everything deactivated again. I just can't stay activated. That's the way it is."
He added: "Usually you don't have to wait like this. At home practising I keep going and keep going. This is different.
"My glutes (gluteus maximus muscles) are shutting off. If they don't activate it goes into the lower back. I tried to activate my glutes best I could but they didn't stay activated."
This is not the first time Woods has cited his 'glutes' as important to both his swing and his recovery.
He wrote on his website in May, five weeks after his surgery: "We knew going into this procedure that it really helps to be strong, especially in my glutes and my abs. I was strong in both departments, and that helps with the recovery and rehab, and you're able to come back faster."
He reiterated the point after missing the cut at August's US PGA Championship, insisting muscle strength was key to him overcoming his back issues and getting back to his best.
"I need to get stronger, I need to get my glutes strong again, my abs and my core back to where I used to have them," he said at the time. "They are just not quite there yet.
"I couldn't make a backswing. Coming through (the ball) is fine, I can't get the club back. (The injury) throws everything off. I can't get anywhere near the positions that I'm accustomed to getting to. I can't do it. I've got to rely on timing, hands, and hopefully I can time it just right.
"It's hard because you want the bigger muscles controlling the golf swing. I have got to rely on my hands to do it."
Billy Horschel was also part of the three-ball with Woods and Fowler and, despite the man who has now dropped to 56th in the world rankings being two over when he was forced to withdraw, the FedEx Cup champion does not believe Woods is too far away from getting back to his best.
"It's unfortunate, I consider him a friend, I want to see him get back to his level of play that we all know he can and I don't think he's that far off," Horschel said.
"If he can just stay healthy and be able to work on it, I think that we would see the results. And it's unfortunate, like I said, it was tough to see him go, but he was in quite a bit of pain out there."
Horschel added: "He toughed it out a lot more than anyone else, than any other playing competitor, they would have dropped off earlier, but he's a fighter, he wants to get the reps in, he wants to play well, and he kept trying to play through it, hoping that it would loosen up.
"I think it was getting there and then we had to wait again... when we made the turn and from there it just, it was real tough to see him walk and even make swings."