England's Sam Horsfield has withdrawn from the U.S. Open after testing positive for COVID-19.

Horsfield shared on Twitter that he tested negative last week before traveling to New York, but subsequently tested positive after arriving on-site at Winged Foot. The 24-year-old is asymptomatic but withdrew from the 144-man field and will now enter a period of self-isolation before returning to competition.

Horsfield joins Scottie Scheffler as the second player to withdraw from this week's event because of a positive test. The PGA Tour had previously gone six straight weeks of competition without a player testing positive.

"It goes without saying that I am hugely disappointed to not have the opportunity to play in my 4th U.S. Open but clearly the safety of the tournament and other players is paramount," Horsfield wrote. "I want to wish everyone all the best for a great week at Winged Foot and thank all the staff at the USGA & PGA Tour in helping me navigate the situation."

Horsfield was viewed as a potential sleeper pick for this week given his successful run in Europe since the break. He earned his first European Tour victory at the Hero Open in August, then followed two weeks later with another win at the Celtic Classic. He finished second on the U.K. Swing points list, with the top 10 players qualifying for Winged Foot, and had moved up to No. 81 in the world.

Horsfield will be replaced in the field by Rory Sabbatini, who will make his 13th U.S. Open start. The alternate list is based off the Aug. 23 world rankings, meaning that former U.S. Amateur champ Doc Redman is now first alternate.