Boston Red Sox starting pitcher Chris Sale delivers against the Tampa Bay Rays during the first inning of a baseball game Monday, Sept. 6, 2021, at Fenway Park in Boston. Credit: Winslow Townson / AP

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

A Red Sox spokesman confirmed the result on Friday morning. The seven-time All-Star had been scheduled to start Sunday in Chicago against the AL Central-leading White Sox.

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.

Any prolonged absence for Sale would be a big blow for the Red Sox, who entered Friday with a one-game lead over the New York Yankees for the AL’s top wild-card spot. Toronto was another half-game back as it tries to swipe the second wild card from its AL East rivals.

Boston has made frequent use of the COVID-19 injury list in the last month, 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.

Eight players remain on the COVID-19 IL, including infielders Xander Bogaerts and Christian Arroyo and pitchers Nick Pivetta, Matt Barnes and Martín Pérez.

Story by Jay Cohen, Associated Press