Three-time major winner Jordan Spieth, who is trying to complete a career Grand Slam at next week's PGA Championship, said on Tuesday he is just back to full strength after contracting COVID-19.

Spieth snapped a four-year win drought since capturing the British Open by taking the Texas Open last month then shared third at the Masters the following week.

He planned to play two weeks ago but has spent four weeks idle since Augusta due to the virus and the need to get back into playing shape ahead of this week's US PGA Byron Nelson tournament in his hometown of Dallas.

"I took kind of a week off, and then I ended up, actually, getting COVID, so then I was out for a little while," Spieth said. "So I'm just kind of starting to get it back the last week or so and get back on track.

"I've only played a couple rounds and so I'm looking to kind of maybe knock a little rust off that I didn't think would necessarily be here."

World No.28 Spieth said he wanted to rest last week because his game did not yet feel 100 percent back on form.

"I feel good. I feel strong. I feel ready to go for a good stretch of golf coming up," Spieth said. "I've been able to do everything I can normally do the last week or so."

Spieth, 27, makes his fifth attempt at the career Grand Slam next week at Kiawah Island. He finished second at the PGA in 2015, the year he won the Masters and US Open, and shared third at the 2019 PGA.

Spieth said he was unsure how he contracted the coronavirus "because nobody I was around ever got it," but he first felt symptoms on April 20.

"It was bad for a day and a half and then it was just kind of annoying for the next five days, kind of lost energy and sinus stuff, and ­after that I started to get full strength back," Spieth said.

"The last week and a half now I've been acting as if it never happened. I've just gone about my days feeling full energy and being able to hit kind of full workouts and practice sessions and all that kind of stuff."

Spieth had to quarantine from his wife, who did not test positive, and stay inside until he was no longer positive.

"I guess it certainly could have been worse," he said. "So I was lucky with that."