Matthew Stafford became the eighth member of the Detroit Lions to be placed on the reserve/COVID-19 list.
Players are put on the list either if they've tested positive for COVID-19 or have been in close contact with someone who has the coronavirus.
A message left with Stafford's agent seeking comment was not immediately returned to ESPN.
When Stafford's wife Kelly was pregnant with their fourth child in May (she has since given birth to a daughter), Stafford said they have been as cautious as possible.
"I think it's in everybody's best interest to be as safe as you can possibly be whether you've got a pregnant wife at home with kids or not," Stafford said in May. "Obviously, nobody really knows, there's not hard data on this yet, on what it does to a pregnant woman or a baby or whatever it is. We're just trying to make sure we're doing whatever we possibly can to limit our exposure.
"Make sure we are at home doing everything that the experts are telling us to do, as much as we possibly can, and we're trying to stay sane and still have a little bit of fun here and there."