Frank Lampard says some context is needed over Kai Havertz's early struggles at Chelsea as he backed the attacking midfielder to show his "undoubted talent" once he fully settles.
The Germany international has struggled to transfer the form he showed at Bayer Leverkusen since joining Chelsea in a reported £72million (€80m) deal in September.
Havertz has just one goal and one assist in 14 Premier League appearances and has been named among the substitutes for the Blues' last three outings.
However, Lampard insists the 21-year-old is still finding his feet after moving to a new country, a period of adaption not helped after being laid low by coronavirus earlier in the season.
"Just as Kai was just coming to terms with the Premier League and he had some really good performances with us he got COVID and he had it quite severely as I think people are really starting to open up about now," Lampard said.
"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. It is something we are trying to help him to deal with.
"The expectation around him, you have to put context into the story. Kai's talent is undoubted. I see that every day. Giving him the time to adapt to the Premier League and to our team is crucial.
"We have seen players come here in the past, didn't really adapt, went elsewhere and come back to the Premier League and absolutely lit it up to unbelievable levels.
"I am not trying to compare Kai directly with that but there are so many stories across the Premier League, not just Chelsea.
"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."
Havertz has created 10 chances in his 14 top-flight appearances this term at a rate of 1.1 every 90 minutes, placing him behind fellow attackers Mason Mount (2.4), Callum Hudson-Odoi (2.7) and Hakim Ziyech (2.8).
He averages just 0.9 shots per 90 minutes, meanwhile, which is 14th on the list of Chelsea players, behind even holding midfielder Jorginho (1.1) and full-back Reece James (1.3).
That is in stark contrast to his impressive figures in the Bundesliga when scoring a record-breaking 17 goals - the most in a single season for a teenager - in 2018-19 and following that up with 12 more last term, on top of six assists.
And Lampard is aware of the demands that come with making a high-profile move, having taken time to get going at Chelsea following an £11m switch from rivals West Ham in the early part of his playing career.
"Transferring leagues to a game that is fast and physical week in, week out, every three days is a big ask and not something that should be expected just because we paid this amount for you or you are an international or your age or how many goals and assists you made," he said.
"You can't take anything as a given in that sense. I thought that with Kai anyway and I was there to help him, I am there to help him when he came. I was excited to take on that challenge with him of how this league is going to be different.
"Let's see how you can adapt because your talents are going to be different in a really positive way and help us. The one thing I certainly know as a coach is that I can rely on is my personal experience when it mirrors up slightly.
"I know I had to do extra work myself. Kai is different to me. Particularly with the knockback of COVID. Now we have to give him time to do the extra work now and it will make him stronger in the end. And remember, he is a young player and he needs time."