Devers and an unspecified number of other players were working out at nearby Boston College and have since tested negative three times.
When tests reveal "pending'' or inconclusive results, the Red Sox have decided to keep those players out of full-team workouts -- even if a player hasn't had a positive test.
"We have to be overly cautious,'' manager Ron Roenicke said.
Devers batted .311 with a league-leading 54 doubles, 32 homers and 111 RBIs in 2019. He is scheduled to get a few at-bats when the Red Sox hold their first intrasquad scrimmage on Thursday.
The Associated Press contributed to this report.