MILWAUKEE (AP) – Chicago Cubs manager David Ross said Tuesday that none of his players have tested positive for COVID-19 as infielder Matt Duffy joined three teammates on the virus-related injured list.

The Cubs already had placed relievers Brandon Workman, Jason Adam and Dan Winkler on the coronavirus-related injured list Monday. Bullpen coach Chris Young and first base coach Craig Driver have tested positive.

“We still do not have any players on the positive COVID list,” Ross said before the Cubs’ game with the Milwaukee Brewers. “I would tell you right now with protocols and being extra cautious, if you have a headache, if you have a runny nose, if you have body aches, if you have just about anything going on that would or could be one of the 10 COVID symptoms, we’re going to err on the side of caution.”

Ross said Driver was in the three-week waiting period between vaccination doses and that Young already had received both shots when they tested positive.

“It’s two weeks after you get the second shot that you’re fully vaccinated,” Ross said. “That would have been Sunday. Chances are (Young) contacted the COVID before Sunday.”

Ross said Driver and Young gave him permission to reveal those details. Ross noted both coaches also were diligent about wearing masks.

“They don’t want to scare anybody,” Ross said. “They think the fact they’ve had the shot is actually a positive and would recommend everybody to get the shot. CY feels completely fine. I think they think the reason why they feel as good as they do is because they’ve had some version of the shot.”

Ross added that “we are taking this seriously” and that “we are trying to get everybody as vaccinated as we possibly can.”

The Cubs filled Duffy’s spot on the roster by adding infielder Ildemaro Vargas from the organization’s alternate site in South Bend, Indiana. Chad Noble, who normally is the Cubs’ bullpen catcher, is handling the bullpen coach responsibilities.