That's the view of former Blues man, and talkSPORT host, Jason Cundy following the news that the striker is set to head back to Inter Milan on loan.
Lukaku arrived back at Stamford Bridge to much fanfare, for a club record fee of £97.5million, a decade on from when he first joined from Anderlecht.
The 29-year-old finished as top goalscorer, but 15 in all competitions was well below the production expected after he hit double that for Inter the previous campaign.
Cundy believes that while some blame can go to Lukaku, he fell victim to injuries the club had and also an unwillingness of manager Thomas Tuchel to adapt more to his game.
He told The Sports Bar: "It's been an absolute disaster. You can't dress it up for anything other than it hasn't worked.
"My own take on this is he suffered as a result, as Chelsea did, and Tuchel had to change too, when we lost, for the long term, the left-wing back and right-wing back.
"Ben Chilwell and Reece James were flying at the beginning of the season. There was a stat at the beginning of the season, the five games they played together the aggregate score was 18 goals scored and one conceded.
"That took a huge amount away from us and I think Tuchel needs a huge amount of credit not only for getting us top four, but also getting us in and around there. Got us to two finals, came up short in the Champions League, pushed Real Madrid as far as we could.
"But those two players were such a huge loss to the way Tuchel wanted to play."
He added: "I thought he was a bit pathetic at times. You see some players who put more in and maybe it was a loss of confidence maybe.
"I'm not convinced he really wanted to be there. His body language at times showed that.
"I felt sorry for him at times because there was runs he was making and there were chances to put the ball into his feet earlier and we didn't put the ball into his feet."
Lukaku had to apologise to fans in January after he gave an explosive interview where he expressed his unhappiness at Chelsea.
Cundy added: "The damage was done. The rot has set in. The interview he gave around Christmas time as well was very bizarre.
"When the interview went out, it was done a few weeks beforehand and not days. He had an injury and came back and wasn't in the team.
"I have a bit of sympathy for him. I felt at times that we didn't play to his strengths. There were a number of times where I felt we could have got the ball into him earlier.
"I felt Tuchel was so concentrated about trying to get the best out of the team because we missed Chilwell and James, the focus of trying to get the best out of Lukaku was lost a little bit.
"Let's have it right, he was poor, but I feel sorry for him because it wasn't just down to him. There were games where I thought 'come on, that's not good enough'."