Frittelli, who missed the cut at the Travelers Championship in Connecticut, is the fourth golfer to test positive since the elite US Tour resumed on June 11.
“I am experiencing no issues and feel great physically and was surprised and disappointed to learn of the positive test,” Frittelli said, adding that he would undergo a period of self-isolation.
“I look forward to getting back on Tour once it’s safe to do so,” he said.
The PGA Tour said in a statement here that it had carried out contact tracing after Frittelli returned the positive result, but was not recommending additional testing at this time.
Day cleared to play as single on Saturday after negative COVID-19 test
The PGA Tour said in a statement that Day, who was originally slated to play as part of a threesome, would tee off alone from the 10th hole as a precautionary measure.
Day, who has competed in all three PGA Tour events since the tour’s resumption following a three-month break due to the pandemic, missed the cut at the Charles Schwab Challenge and RBC Heritage.
The Australian, who opened with rounds of 67 and 69, was at four-under-par overall after 36 rounds, nine shots behind leader Phil Mickelson.
Nick Watney last week became the first Tour player to test positive, and Cameron Champ did so at a pre-tournament screening this week.
World number four Brooks Koepka and Northern Ireland’s Graeme McDowell withdrew from the Travelers as a precaution after their caddies tested positive. The two golfers tested negative.
World number five Webb Simpson opted out after a family member tested positive, while Koepka’s brother Chase withdrew as he played a practice round with Brooks and McDowell.
Denny McCarthy, the third golfer on the Tour to return a positive test, withdrew on Friday, while Bud Cauley, who played alongside McCarthy in the opening round, dropped out as a precautionary measure.
“All follow-up tests as a result of potential contact with McCarthy were negative,” the PGA Tour added.