First the interview, now the invisibility. Romelu Lukaku has mostly been a conundrum since returning to Chelsea last summer and, while the £97.5m striker has not done much talking off the pitch since that ill-advised chat with Sky Italia at the end of December, nothing summed up his struggles more than when he produced a performance of record-breaking anonymity against Crystal Palace last Saturday. This was Lukaku at his most laboured, predictable and disconnected from his teammates. He touched the ball a grand total of seven times, the fewest in 90 minutes of Premier League football for any player since Opta began keeping track in 2003, and nobody was about to argue he was merely keeping his powder dry for the big moments. Even Thomas Tuchel, who desperately needs the Belgian to find form, is not putting a positive spin on the numbers. Chelsea’s manager understands their significance and he was unsure whether he can help Lukaku by tweaking his tactical approach when the European champions host Lille in the last 16 of the Champions League on Tuesday night. “What can I do?” Tuchel said. “I don’t know. We have to deal with it. The data is out there and the data speaks a certain language. He was not involved in our game. It’s not what we want or Romelu wants but it’s not the time to laugh and make jokes about him. He’s in the spotlight and we’ll protect him.” It did not sound as if the mood is going to become cheerier in the near future. True, Lukaku scored twice when Chelsea won the Club World Cup this month. Yes, he should fancy his chances of hurting Lille given the French champions are floundering this season. But no, it would not be a great surprise if it turns out to be another evening of Lukaku waiting in vain for quick balls to be slid down the channels, his teammates ignoring his prompts and Tuchel despairing at his marquee signing looking so out of place. This was not part of the plan when Chelsea bought Lukaku. The 28-year-old had just fired Internazionale to the Serie A title and it seemed he was going to prove similarly inspirational in Chelsea’s attempt to challenge Manchester City and Liverpool. Lukaku was looking an uneasy fit even before an ankle injury further disrupted his momentum in October. An immobile presence, he does not make it easy for Chelsea to attack with fluidity. Increasingly there is a sense of Tuchel compromising his beliefs by sculpting everything around a target man and the problem is exacerbated by Chelsea’s reluctance to play to Lukaku’s strengths, often leaving him frustrated by opting for a controlled buildup. Nobody is adapting. It is not simply down to Lukaku. Kai Havertz, Callum Hudson-Odoi, Christian Pulisic and Timo Werner are not providing for him and do not score enough. Mason Mount, who is unlikely to return from an ankle injury until Chelsea face Liverpool in the Carabao Cup final on Sunday, has had a stop-start campaign and Hakim Ziyech remains inconsistent despite chipping in with some important goals. In that context it is no wonder Chelsea remain a cup team rather than one capable of challenging for the title. They do not create or shoot as much as City and Liverpool, raising questions over whether the tactics are too restrictive. “Maybe,” Tuchel said. “There is a history of strikers struggling at Chelsea so it is not the easiest place in the world for strikers. I don’t know exactly why. We want to be a hard-working group that is not shy to make it physical and not only a skilful game.” For Lille, that was a reminder that Chelsea still know how to play a cup tie. They conceded twice in the knockout stages of the Champions League last season and their defensive prowess will make them contenders again. They are dangerous in these situations but they cannot merely rely on their defence. They are weaker on the left without Ben Chilwell and, although Reece James is close to a return on the right, contractual uncertainty hangs over three key players. César Azpilicueta could join Barcelona at the end of the season, talks with Andreas Christensen have broken down and Antonio Rüdiger is yet to sign an extension despite being offered about £170,000 a week. Gaps have appeared, gaps that would be easier to hide if the attack began to function. Ultimately Tuchel knows he can trust his defenders. The questions are at the other end and the focus has to be on Lukaku somehow developing an understanding with his fellow forwards. They have to accept more responsibility and Tuchel has to give them a spark. A £97.5m striker having seven touches a game is unsustainable and, unless something changes, it is hard to see Chelsea holding on to their European crown.