"I use it as much as I see it out there," he said after shooting a 3-under 69, putting him four shots back after the opening round.

American Champ was added to the field at the Detroit Golf Club under a modified PGA Tour policy that allows players who test positive for coronavirus to be eligible if they had no symptoms and get two negative test results at least 24 hours apart.

Champ, however, said he does not believe he ever had COVID-19.

"Through the specialist that we worked with, at this point it's clear that I never had it," the 25-year-old added.

"Still being precautious because if I happen to do get it, then it affects my family deeply."

The decision to let Champ play on the eve of the tournament was the latest change to an evolving "Health and Safety Plan" as the tour enters its fourth week back from the pandemic-induced shutdown. Champ is among six players and two caddies on the PGA Tour who have tested positive.

"About 4:30 (Wednesday) night we got the call saying, 'Do you want to play?'" Champ recalled.

"I'm like, 'Of course I want to play.' I had to rush here and was able to make it in time to tee it up."

Ricky Elliott, the caddie for Brooks Koepka, tested positive before the Travelers Championship last week in Connecticut, and then had a negative test. Webb Simpson said the same thing happened to one of his daughters, who tested positive initially before another test was negative.

Champ tested positive on June 23 and withdrew from the Travelers Championship. The tour said he had three negative tests over the 72 hours. After flying from Houston on Thursday morning, he was tested again in Detroit and was cleared to play.

Champ had back-to-back bogeys early in his round before closing his front nine with three birdies in a five-hole stretch. He had another bogey on his 11th hole and bounced back again with three birdies on his back nine.

"It was definitely a little shaky start, but like I said, it was last minute to be playing," he said.

Australian Associated Press