Patrick Reed described his frightening fight with bilateral pneumonia on Thursday, saying "battling for my life" was even harder with his family barred from his hospital.

"(Doctors) were sitting there telling me that to make sure you text your family quite a bit, talk to your family, because you just don't know," he said of the shaky prognosis in the first two days of his illness.

"I was battling for my life. With how the hospitals are these days because of Covid and everything that's going on ... they won't allow people in there, so it's only you in there. So I'm sitting there and those first two days the only thing that was going through my mind is, I'm not going to be able to tell my kids goodbye. It definitely puts you in a dark space."

Reed, 31, said he'd been feeling fine until the pneumonia hit him "like a brick”.

"I went from feeling OK to literally feeling like I couldn't breathe and was almost drowning in air."

He was hospitalized in Houston, Texas, and was discharged on August 23.

Reed, who said he received a Covid vaccine about a month ago, tested negative for Covid before he was discharged.

But he said he wasn't tested when he arrived at the hospital, and doesn't know if his pneumonia was linked to coronavirus.

"I had bilateral pneumonia in both lungs, and that's what they were treating me in the hospital," Reed said. "And it was scary because it was in my lower lobes, which is where a lot of deaths and people pass away from."

Reed said he hit balls for the first time on Monday, with doctors monitoring his reaction. He and his caddie took a van service from Texas to Atlanta for this week's season-ended Tour Championship because he wasn't cleared to fly in a pressurized airplane cabin.

"The way everyone on my team kind of makes it sound is once this week's over, I'm full go to be able to do exactly what I want," he said.

In his first round in 25 days, Reed carded a two-over-par 72.

He hit just five of 18 greens in regulation, but the former Masters champion got up and down for par eight times and for birdie once.

"My energy was OK," Reed said. "My speed is not there yet, obviously. But the good thing is my short game didn't leave me. My short game was pretty good today."

That was good news for Reed's hopes of getting a nod from US Ryder Cup captain Steve Stricker, who will make his six captain's picks on September 8.

The match play showdown between the United States and Europe will be held at Whistling Straits in Wisconsin September 24-26.

"(Stricker) came out to me when I was on nine and I hit a hybrid into nine to eight feet, and I made the putt for him," Reed said.