In a conversation with Sky Sport Italia recorded three weeks ago but released on Thursday, Lukaku suggested he was "not happy" because "the coach has chosen to play with another system."
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The 28-year-old joined Chelsea from Internazionale in a €115 million (£97.5m) deal last summer and went on to suggest he wanted to return to the Serie A side "not at the end of my career, but at a still good level to hopefully win more."
Although Lukaku has scored three goals in his last four games to represent an upturn in his personal form, the Belgium international's comments represent another difficult situation for Tuchel as a patchy run of form has left them eight points behind leaders Manchester City before facing Liverpool at Stamford Bridge on Sunday.
Speaking on Friday at a news conference ahead of that game, Tuchel said of Lukaku's comments: "We don't like it, of course because it brings noise that we don't need and it is not helpful.
"But on the other side we don't want to make more of it than it actually is. You know very well how it is. It is very easy to take lines out of context. It is very easy to shorten lines, make headlines and then later realise that it's maybe not so bad and not what he meant.
"Let's be honest, I don't like it because it is noise that we don't need. We need a calm environment and focus and this does not help. If it is an interview from a person of that kind of interest, that important player. I totally understand the process.
"That's why it is a lot of noise, not a little bit, a lot of extra noise. But still, we are not here to just read the headlines and maybe we can take the time to try to understand what's going on because it does not reflect the daily work, it does not reflect the daily attitude, it does not reflect the daily behaviour that Romelu shows here at Cobham.
"You need to ask him, not me, I cannot help you further with this because I was surprised."
Tuchel said he plans to speak with Lukaku to understand the full picture but went on to explain why some tension among the players could be a positive.
"The dressing room is not necessary always to be in harmony," he said. "It is absolutely not necessary to be successful. We don't have to hug each other, love each other every single day.
"Sometimes [it is] good to be on the edge, sometimes good to be a bit like in this harmony when it is in between certain boundaries.
"With Romelu, I don't think that anybody in this building is aware that he is unhappy and that's what makes us very surprised by these statements. First of all, we need to check because I can see no reason why this should be like this. That's all I can say about it and wait what Romelu says and then we will deal with it."
Tuchel confirmed "it seems like the season is over" for Ben Chilwell following a knee operation to repair anterior cruciate ligament damage while Reece James will have a scan later on Friday to determine the extent of his muscular problem.
Chelsea are also facing late fitness tests on a number of players including Thiago Silva, Andreas Christensen, Timo Werner and Ruben Loftus-Cheek. Tuchel employed an unusual analogy to describe how badly his squad has been stretched by illness and COVID-19 during a run of four wins 10 games across all competitions.
"It is like squeezing the same lemon over and over again and we always expect fresh juice out of it," he said.
"It is hard because we are so ambitious and it is hard for the team to take these results and stay positive. We know we can play better, everybody is fully aware."