Boston ace Chris Sale has tested positive for COVID-19 again, sidelining the left-hander while the Red Sox fight for positioning in the crowded AL playoff picture.

Sale had been scheduled to start Sunday in Chicago against the AL Central-leading White Sox. The seven-time All-Star also had a mild bout with COVID-19 in January that required him to quarantine for two weeks.

"At this point, nothing shocks me, to be honest with you," manager Alex Cora said before Friday night's 4-3 loss to the White Sox in the series opener. "On a daily basis we just go through a process and we just hope for good news. This is where we're at."

CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COM

The Red Sox have placed 17 players on the COVID-19-related injury list since Aug. 3, including infielders Xander Bogaerts and Christian Arroyo and pitchers Nick Pivetta, Matt Barnes and Martín Pérez.

Bogaerts was reinstated Friday and returned to the starting lineup against the White Sox. But designated hitter J.D. Martinez was scratched because of back spasms.

It was Bogaerts’ first game since he was pulled from an 8-5 loss at Tampa Bay on Aug. 31 after the Red Sox found out he had tested positive. The three-time All-Star had to stay behind in Florida after the team departed.

Bogaerts said he felt fine the whole time.

"It was boring, man," he said. "I wouldn't want that for anyone. At least if you're in Boston you're at home."

Left-hander Darwinzon Hernandez was activated from the 10-day injured list after being sidelined by a right oblique strain, and right-hander Kaleb Ort was promoted from Triple-A Worcester. Hernandez pitched 1 1/3 scoreless innings in the loss to the White Sox.

The Red Sox also placed infielder Jonathan Araúz on the COVID-19 list, and lefty Austin Davis went on paternity leave. The move with Araúz is precautionary; he has some symptoms, but he has tested negative multiple times, according to the team.

The 32-year-old Sale missed all of last season recovering from Tommy John surgery. Since returning Aug. 14, he is 3-0 with a 2.52 ERA.

"It's unfortunate, but he'll be back," Cora said. "He feels good. He actually feels great, and hopefully he can come back right away, right after his X amount of days."

Sale likely will have to stay away from the team for at least 10 days, though Major League Baseball has made exceptions for individuals cleared by its medical experts, based on not being infectious.

Any prolonged absence for the lefty would be a big blow for the Red Sox, who have a one-game lead over the New York Yankees for the AL's top wild-card spot.

"This is our reality and we've got to keep going," Cora said.

Cora said Pivetta is feeling good, and he is one option when it comes to replacing Sale on Sunday. Right-hander Connor Seabold is on the team's taxi squad for the road trip, and Cora said there's a good chance he will start Saturday in his big league debut.

Pérez was in Worcester on Friday, and Cora said the plan was for him to throw a bullpen session and then pitch in a game on Sunday.

While Boston has made frequent use of the COVID-19 IL, but it looked as if it was turning a corner before Sale's positive test. Left-hander Josh Taylor was reinstated on Monday, and position players Kiké Hernández and Danny Santana returned to the active roster on Tuesday.