The Belgium international has been heavily linked with a move to Everton, Liverpool and Tottenham Hotspur in recent weeks.
Sell him? That will eventually happen, but the price some clubs will look to pay for Lukaku won’t be the same as what Chelsea value him at
Lukaku, who spent a season at West Bromwich Albion in 2012/13, scored 15 goals and made six assists in 31 Premier League appearances during his Everton loan last term.
But former Chelsea striker Cascarino feels Lukaku is better utilised as an impact substitute, questioning his spell at Everton.
“I’ve said before that I totally believe Mourinho doesn’t think Lukaku is good enough. If he thought Lukaku could come in and do a job it would have been a no-brainer, but I don’t think he’s ready,” Cascarino told talkSPORT.
“I’m not his biggest fan. I’ve looked at him over the last couple of years. He went to West Brom, was subbed lots of times, came on and had a great goalscoring record as a sub. He got a few goals and had a great run at the end of the season. Everton fans are also very undecided about him.”
He added: “Sell him? That will eventually happen, but the price some clubs will look to pay for Lukaku won’t be the same as what Chelsea value him at. It’s a real conundrum for the player because he obviously wants to play football.
“He had times when he done very well for Everton; I saw him lots of times when he was mediocre. I felt his first touch certainly wasn’t up to the standard required of a team fighting at the top of the table.”
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news