The caddies for Brooks Koepka and Graeme McDowell have tested positive for the coronavirus, and McDowell withdrew Wednesday from the Travelers Championship in Connecticut.

McDowell said Koepka also was planning to withdraw, though the four-time major champion remained in the field early Wednesday afternoon.

“The snowball is getting a little bit bigger,” McDowell said as he began the 1,200-mile drive from the TPC River Highlands to his home in Orlando, Florida.

McDowell tested negative, though he suspects he has the virus and decided to drive home to start his self-isolation. He said Ricky Elliott, a longtime friend from Northern Ireland and Koepka’s caddie, received a positive result.

Cameron Champ tested positive on Tuesday, the second player to test positive in the last five days. Still to come are results from all players, caddies and essential personnel at the Travelers Championship, the third tournament since the PGA Tour ended its three-month shutdown because of the COVID-19 pandemic.

McDowell played a practice round Tuesday with Koepka and British Open champion Shane Lowry. McDowell said he heard from Lowry, whose test was negative.

“The problem is, people are out here passing tests when they could still have the virus,” McDowell said. “That’s what we’re learning. Ricky passed a test on Monday and he just failed it this morning.”

McDowell’s caddie, Ken Comboy, never made it to Connecticut. McDowell missed the cut last week at the RBC Heritage on Hilton Head Island, South Carolina. He felt a sore throat and reported it on the daily questionnaire, and then Comboy drove back to Hilton Head from Orlando to take another test. That was the quickest way to get the results, and he received them Tuesday night while waiting to fly.

McDowell says he was at a memorial service on June 15 with Comboy, Elliott and McDowell’s trainer, after which they drove up to Hilton Head.

McDowell said he was feeling a little fatigued at the end of last week, which he wrote off to having not competed in a tournament for three months and then playing two straight weeks.

“I had been feeling a little off color, but not with alarm bells ringing until Kenny failed,” he said.

The PGA Tour’s return to tournaments started with a perfect record — 487 tests for players arriving at Colonial in Fort Worth, Texas; 98 players on the charter flight to South Carolina; 369 tests at Hilton Head Island. All came back negative.

Nick Watney was the first player to test positive, on Friday at the RBC Heritage. Watney, who had tested negative three days earlier, asked to be tested again when his Whoop wristband — which measures various health metrics — showed an increase in his respiratory rate.

Justin Thomas, who also wears the wristband, said the tour has acquired Whoop straps for players and caddies.

“It’s crazy to say, but (without) his Whoop device we could have been screwed right now because he could have played the rest of the week and ended up contaminating or infecting many other people,” Thomas said Wednesday.

Will Ahmed, the CEO and founder of Whoop, said the tour has acquired more than 1,000 of the straps and that the company was working to integrate the straps with “everyone in the PGA Tour universe.”

McDowell said he would take two weeks off and hoped to return in July for the first of two weeks in Ohio. But that depends on if the PGA Tour is still going on.

Commissioner Jay Monahan scheduled a news conference for Wednesday afternoon.

“Do we shut down, start up in a month’s time, two months’ time? You come back and what’s changed,” McDowell said. “I think the tour is doing a pretty good job. It’s just so difficult to control everybody outside the gates.

“We have to get through to the other side of this.”