The PGA stated 16 many others were analyzed, together with McCarthy's caddy, the two gamers who golfed along with him throughout the to start with round, Matt Wallace and Bud Cauley, and their caddies. Nick Watney withdrew after feeling symptomatic entering the second round of the RBC Heritage Championship last week, tested positive and withdrew.
The world No 1 sank a six-foot putt for a birdie two at 11, but despite playing consistently thereafter he could not improve his position through a frustrating run of seven straight pars.
McCarthy said he felt exhausted on Thursday, but he thought it was because of how much he had been exercising earlier in the week.
"It really was a moving day, so I was just trying to get as low as I could, and if anything just use the leaderboard as motivation", said Todd, who had five birdies on the front nine and four on the back. "Dave tested negative, we are all clean, we went out and played, that's pretty much it for me".
Koepka's brother Chase and Webb Simpson withdrew having been in close proximity with a person who had subsequently tested positive.
Graeme McDowell did not compete because his caddie, Ken Comboy, also tested positive.
The Englishman and his caddie also tested negative prior to the second round, with Wallace believing they'd done every thing correctly to help you to continue.
PGA Tour commissioner Jay Monahan thanked McCarthy for "doing the right thing" in requesting an additional test on Friday before heading to the course.
The third member of their group, Bud Cauley, tested negative but had been experiencing some symptoms consistent with the disease.
The 23-year-old Morikawa said he's not playing next week in Detroit but plans to play the two events at Muirfield Village, the second of which is the Memorial.
Collin Morikawa came into the week riding a streak of 22 consecutive cuts made to begin his professional career, but finally ran out of gas, falling three short of matching the record held by Tiger Woods. "Now I guess we're going to stop talking about [the streak] and I can go and just go on to next week".
"I just couldn't get the ball in the hole". He missed the cut after shooting 72 in the second round.