Manager Dusty Baker said he couldn't give specifics, but the designation is a sign the players have tested positive for or have come in contact with someone who has COVID-19.
Baker said Greinke will miss his next start. The right hander is 11-5 in 27 starts this season with a 3.66 ERA and 110 strikeouts.
Baker said the team had planned to go to a six-man rotation when right-hander Jose Urquidy (right shoulder) returns from the injury list when rosters expand. Now they'll probably stay with a five-man rotation, he said, until Greinke returns.
"It seems like that's been the case this year, you know, we get one back and we lose another," Baker said. "But at least we have enough depth to get one back."