SAN FRANCISCO — It’s possible COVID-19 has made its way within the walls of the Giants clubhouse again this season.

The team placed infielder Thairo Estrada on the COVID list before Sunday’s game against the White Sox. Although Estrada has not yet tested positive, he has shown symptoms for more than 24 hours, manager Gabe Kapler said.

“We’re going to test him and see where we are,” Kapler said. “This is what we thought made the most sense to protect both Thairo and our roster today.”

In a corresponding move, the Giants recalled Yermín Mercedes from Triple-A Sacramento.

Estrada was a late scratch from the lineup Saturday with illness. His symptoms so far have been a sore throat and a headache, Kapler said. Under MLB’s protocol, players are allowed to be placed on the COVID list “for symptoms that require further assessment,” even if they have not tested positive.

Estrada was briefly in the Giants clubhouse Sunday morning and was not wearing a mask.

“We moved him through the clubhouse as quickly as possible,” Kapler said, adding that no other players have exhibited symptoms.

If his test results come back positive, Estrada will be the sixth member of the Giants to catch the virus this season. In a previous outbreak at the end of April, Mike Yastrzemski, Brandon Belt, Zack Littell, Dominic Leone and Steven Duggar all missed time on the COVID IL.

Each player missed seven games; MLB’s COVID protocols say 10 days is the baseline absence following a positive test.