Rory McIlroy labelled suggestions the Travelers Championship be called off amid positive coronavirus tests as "silly".

Brooks Koepka withdrew from the PGA Tour event after his caddie, Ricky Elliott, was one of three people to test positive for COVID-19 ahead of the tournament.

But four-time major champion McIlroy dismissed the calls for the event to be called off, backing PGA Tour commissioner Jay Monahan.

"I thought Jay did a wonderful job yesterday, just relaying the information and where the PGA Tour stands and where we're going going forward," the world number one told a news conference after shooting a first-round 63.

"You hear one or two positive tests and people are panicking, and I saw a couple of calls to shut the tournament down, which is silly from my point of view.

"You know, I thought he did a really good job explaining. There's been almost 3,000 tests administered. The percentage of positive tests ... it's a quarter of a per cent.

"I think as a whole, it's been going really well. There's a couple of loose ends that we needed to tidy up, and I think we've done that. I feel like the mood and the tone of the event was probably lifted by Jay yesterday."

McIlroy's seven-under 63 saw him sit in a tie for second, three shots adrift of leader Mackenzie Hughes.

The Northern Irishman was satisfied with his round, saying: "I played well from the start. I hit two shots into our first hole, the 10th, didn't capitalise on that.

"I had a chance on 12, didn't capitalise on that. But sort of the round got going with the eagle on 13, birdie on 14, and then the tee shot into 15.

"That was a new three wood I put into play last night. I hadn't even hit it on the course. So my first shot with it was off 10, and then second shot was the one on 15. It's worked out pretty well. Nice little change."