N'Golo Kante will miss Chelsea's Champions League match on Wednesday against Juventus after testing positive for COVID-19.
It is not known if Kante has received the vaccine.
Thomas Tuchel, who is fully vaccinated, admitted he is unaware of how many Chelsea players have received the jab but refused to call for a mandatory uptake despite an apparent reluctance among many footballers to take it.
"We are only a reflection of society and the players have a free choice if they want to get vaccinated or not," Tuchel said on Tuesday at a news conference.
"I think we should accept it and this is more or less everything I can say. I know the situation is far from over and all the time somebody gets it here from us and from our crew, it make you very aware it is not over. I hope it gets as less as possible but I clearly don't have the solution for it.
"It would be easy to say yes [the players should get the vaccine to set an example] now and get applause from a lot of people but at the same time, do I have the right to say it? I'm not so sure. I can make the decision for myself and everybody else needs to reflect about it, take a risk or not."