Frank Lampard says some of his players are struggling with coronavirus for longer than others, including Kai Havertz, who the Chelsea boss says he has his full faith in.
Havertz joined Chelsea for £70m in the summer transfer window and has managed just a goal and an assist in 14 Premier League matches. .
But Lampard has backed the 21-year-old to overcome his Covid-19 struggles and adapt to the rigorous demands of the Premier League.
Bruce the 'fall guy' amid Newcastle takeover, says manager's son
"Just as Kai was coming to terms with the Premier League and had some really good performances with us, he got Covid and he had it quite severely. I think people are really starting to open up about now," he told reporters.
"I have read a few things recently about how much people can suffer with it now. Some people are asymptomatic. He definitely has had a bit of a fallout with that physically and I speak with him a lot and we know that.
I have full belief in him. We need to give him that time, particularly because of the Covid situation - that is a problem. That is not a non-issue; it is an issue that is related beyond his illness.
Real aim for Camavinga and Alaba double swoop - Euro Papers
Chelsea have lost their last three matches and have drawn one in their last five with the west London club currently placed sixth in the table.
Ahead of Sunday's game against Manchester City, Lampard admits Covid-19 has had a damaging, lasting effect on his players.
He told Sky Sports: "Very challenging, not just for me but the medical team and sports science because some players are asymptomatic and come back training within a few days and reach their top level, but then there are some players who take longer.
"They report tiredness and fatigue and because everything is so new, we don't have anything to gauge it by. We don't have the right methods to know how to get players back to a level as quickly as possible.
"It's not just us but a problem for the league. This year is different and will be different until we get to the other side."
World Cup Qualification UEFA
Germany qualify for 2022 World Cup, Netherlands thrash Gibraltar
Opinion: Loftus-Cheek (and the academy) is Tuchel’s not so secret weapon