Chelsea manager Thomas Tuchel has said Romelu Lukaku's current struggles in front of goal is due to the relentless schedule of playing regularly for club and country.
The Belgium forward rejoined Chelsea from Inter Milan in August for a club-record fee of £97.5 million ($134.7m) in the summer.
Lukaku, 28, hit the ground running in his second spell at the Premier League club, grabbing four goals in as many games but has not found the net since scoring against Zenit St Petsersburg on September14.
Tuchel, speaking ahead of Wednesday's Champions League match against Swedish side Malmo in London, insists his loss of form can be put squarely down to playing too often with the national team.
“In this very moment I feel Romelu is a bit overplayed, I think he played too many competitions over the summer, too many competitions with the national team,” said the German manager. “And now he has played the Nations League [Belgium finished fourth at the finals earlier this month].
“He is a fantastic athlete and such a competitive guy that he digs in deep, he wants to win these things and he never takes it easy and judges games. He wants to be out there and win.
“So I know how much he wanted to have a good outcome for Belgium in the Euros, and the Nations League meant a lot to him too.
“It was a huge match for him personally, it means a lot to him to play for his country. So he takes it really seriously. And if it doesn’t go well he always takes it on his shoulders.
“For me he is overplayed a little bit. And this is the key point. Once he finds his rhythm he will find things a bit easier. But it’s difficult to judge whether he needs a break or he needs to keep playing.”
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Tuchel also says Lukaku is not alone in his Champions League-winning squad. “It’s the same for some other players too, Mason [Mount] and Jorgi [Jorginho, who play for England and Italy, respectively].
“They have a lot of weight to carry for their countries. They take it and they love it, they are competitors.
“But if you play a thousand matches a year it can feel a bit heavy, although they love the game. They are such good guys but this is what I feel just between the lines.”
Chelsea, the defending European champions, are second in Group H of the Champions League after two games following defeat to Juventus last month.
They remain top of the Premier League after eight matches but Tuchel admitted their form had dipped, with one major reason being the quantity of games for top players.
“It is important that we are not too critical of ourselves,” he said. “You have hard moments, you fight through them and be a team nobody likes to play against.
“It isn’t easy for any team in the Premier League to win any game, so maybe this is normal and we have to embrace the situation that is difficult at the moment. We are finding our ways to win the games at the moment.
“There is still room to improve and we lack form and freshness, a bit of joy, and for me a key reason is not the mentality or attitude.
“If you think about it, if you travel through time zones, in a hotel, then you change the hotel, one day at home, see family, then back to the hotel, play at Brentford, then it’s Champions League, it can be tiring … this is simply too much football in too many competitions.”