SEATTLE -- The Boston Red Sox activated reliever Hirokazu Sawamura from the COVID-19 injured list and returned left-handed pitcher Austin Davis from the paternity list on Monday, giving a boost to their bullpen going into a key series against the Mariners.

Red Sox manager Alex Cora said there could be more players coming off the COVID-19 injured list in the coming days. Left-hander Martin Perez is expected to be activated on Tuesday, and Cora is holding out hope that left-handed starter Chris Sale could return this weekend against the Baltimore Orioles.

Sale is on the COVID-19 injured list, but Cora said he has shown no symptoms. Sale tested positive late last week and was scratched from his scheduled start on Sunday.

The Red Sox have nine players on the COVID-19 injured list.

In his first season in the majors, Sawamura has become a key member of Boston's bullpen. The right-hander is 4-1 with a 3.09 ERA working primarily as a seventh- or eighth-inning option for Cora. Sawamura hasn't pitched since Aug. 28 against the Cleveland Indians.

Going into Monday's game against the Mariners, Davis had a 4.61 ERA in his time with the Red Sox, and he gave up no hits while recording a strikeout in one-third of an inning in Boston's 5-4 loss to Seattle. He has appeared in 15 games for Boston since being acquired from the Pittsburgh Pirates.

Boston optioned lefty Stephen Gonsalves and righty Brad Peacock to Triple-A Worcester to clear roster spots for Sawamura and Davis.

Cora said Sale is trying to stay as active as possible so that once he is cleared to return, he can rejoin the rotation.

"I do believe he has a huge patio at the house, so I bet he's either throwing rocks to the trees or throwing baseballs to a net," Cora said. "I believe he'll find a way to keep his arm sound, and he'll be ready whenever."

The Associated Press contributed to this report.