Romelu Lukaku was "bullied" by Andreas Christensen and Cesar Azpilicueta on Sunday and does not turn up in big games.
That is the opinion of former Chelsea, Blackburn and Celtic forward Chris Sutton.
Lukaku failed to find the back of the net as Manchester United lost 1-0 at Stamford Bridge. The Belgian striker has now gone seven games without a goal.
"At 6ft 3in, Romelu Lukaku is one of the most physically imposing forwards in the Premier League," Sutton wrote in his column for the Mail.
"Yet he was bullied all afternoon by Andreas Christensen — on only his fourth league start for Chelsea — and Cesar Azpilicueta who is almost half a foot shorter.
"The accusation levelled at Lukaku is that he does not turn up for the big games. I do not like calling players out for a lack of effort but on this evidence, it is hard to argue."
Ex-Arsenal man Ian Wright, however, argued on Match of the Day that Lukaku was not getting the service he needed to score.
"When you aren't scoring, you look at two things - am I getting the service and am I making the right runs?
"I think it is a combination of the two.
"He is well capable of scoring in this team but he is making the wrong moves and the chances aren't coming.
"The service is terrible. Nobody is helping him. I am not sure how he is going to score goals if they keep playing like this.
"[Henrikh] Mkhitaryan had six passes to him. That is nowhere near good enough."