Costa revealed earlier this month that Antonio Conte had told him he was not part of his plans for 2017/18, and the Blues have been heavily linked with their former player Lukaku, who joined them aged 18 in 2011 but left four seasons later after making only 15 first-team appearances.
The Belgian has scored 53 goals in 110 Premier League appearances since 2012/13, however – including a season-best 25 last term for Everton – but Cascarino is still not convinced.
“To replace someone of Costa’s quality, you’re looking beyond Lukaku,” the former Blue told FourFourTwo. “He’s not the finished article.
There are players out there, but there aren’t many of that proven quality to replace Diego Costa
“You should be looking at [Robert] Lewandowski or [Pierre-Emerick] Aubameyang, who’s lightning quick; [Antoine] Griezmann or someone like that.
“It’s hard, but sometimes transfers you think are impossible actually happen in the end. There’s [Alvaro] Morata at Real Madrid, who Conte signed at Juventus, but he might not trust him.
“There are players out there, but there aren’t many of that proven quality to replace Diego Costa.”
Despite singing Costa’s praises, however, Cascarino sympathised with Conte’s decision to force the Spain international into leaving.
The 54-year-old conceded that the former Atletico Madrid striker’s attitude was something the Chelsea manager didn’t want in his squad.
“To be honest, I envisage that Monday morning at Cobham, Costa was knocking on the manager’s door moaning about something,” said Cascarino.
“There are certain players who just drive you crazy. He’s had three good seasons, won titles, but he doesn’t want to be there. You don’t ever keep a player who doesn’t want to be at your club.”
Cascarino, like many others, has been excited about 18-year-old Monaco forward Kylian Mbappe, and thinks Chelsea should be doing everything they could to make him a part of the squad despite his tender years.
There are certain players who just drive you crazy. He’s had three good seasons, won titles, but he doesn’t want to be there
The France international burst onto the scene last scene and scored 26 goals as his side picked up the Ligue 1 title and reached a Champions League semi-final.
“I’d go straight in for Kylian Mbappe at Monaco,” Cascarino said of his No.1 target. “You might end up spending £50m more, but you have potentially the best player in world football.
“Yes, it would cost in excess of £100m, but Chelsea are one of the few clubs who could do that.
The only thing I’d wonder about is that he’s a teenager, but he’s the most dangerous striker there is.”
Cascarino has worries about the future of Chelsea’s title-winning side, and feels several players who led them to the trophy may not be there in August.
“[Nemanja] Matic is leaving and I think this will be the biggest break-up of a title-winning team we’ve seen for a long time,” he said.
“I can see Costa going, and [Eden] Hazard as well as Matic. That’s a £200m turnaround which enables Conte to bring in his players. You could see that team decimated.
“They need a couple of wing-backs, even though [Victor] Moses and [Marcos] Alonso did really well last season. They need another centre-half, too. I think opposition gave the back three a bit too much respect last season and didn’t pressurise them high up the pitch.”
Conte got the best out of five or six players and that’s an incredible achievement
Cascarino was glowing of Conte’s management last season, and highlighted the Italian boss’s ability to extract maximum ability from his players.
“You have to give him so much credit because he managed to get the best out of a team, many of whom won’t be there next season,” he told FFT.
“People like Moses, Alonso, Gary Cahill. He changed the system, which helped, but he got every last bit of sweat out of the team.
“Compare it to the previous season: [Thibaut] Courtois was poor, Hazard was poor, Costa was poor, Matic was poor. Think about Pedro. The year before, he was dreadful, but he was brilliant. He got the best out of five or six players and that’s an incredible achievement.”
Words: Ed Mackey
Tony Cascarino was speaking at the £1,000,000 guaranteed partypoker Grand Prix UK, Nottingham. For information www.partypoker.com
