Neil Warnock, the former Cardiff City manager, prefaced his claims by admitting he didn't want them coming across as "sillily". But he still declared United signing Grealish this summer could give them the Cantona effect.
Warnock said of the Aston Villa captain: "I don't want you to use it sillily [sic] but you know when you think of Cantona and people like that who just have something magical.
"He just fits that bill as a young one, doesn't he and I think he would be a great signing."
Just days previous, former United goalkeeper Mark Bosnich did the same, this time drawing a likeness between United's new addition Ighalo and Cantona.
"You never know. A long, long time ago Manchester United signed a certain Frenchman (Eric Cantona) who no one really expected much from and he ended up propelling them to one of their most successful seasons of all time," insisted the Aussie.
Ighalo's a good player. A good striker. Who at 30 can offer United some short-term know-how during this loan from Shanghai Shenhua. But there's no comparing the Nigerian with Cantona.
And as for Grealish, again there's just no comparison. The midfielder would arrive with his best years ahead of him. The expectation that he grow as a player as this young team Ole Gunnar Solskjaer puts together continues to develop.
In contrast, Cantona was a transformative signing for United. Not just for the team. But for the club itself. It can be argued the size of Manchester United today was built much off the shoulders of what the Frenchman brought to the club during his years there.
Back in 1992, Cantona's move from Leeds United was as big as it gets. He'd just inspired his team to the First Division title and for the start of the following season had hit a hat-trick in the Charity Shield against Liverpool.
His move to United stunned fans around the world. Think Mo Salah quitting Liverpool for Old Trafford. This was the equivalent 28 years ago. Sir Alex Ferguson has talked about Cantona being the player who grabbed hold of his wrist and helped him unlock the door. But it went further than that. Much further. Cantona had an influence on everything through the club. The senior players. The juniors. The diet. The training. And the genius of Ferguson was that he recognised the positive impact Cantona was having and so treated him differently.
After all, Howard Wilkinson couldn't get shot of the Frenchman quick enough in that second season together. Those discipline issues that had driven him out of France were apparently rearing themselves again at Leeds.
But he did actually move to Elland Road as an established France international. The problem for Cantona was his temper, which included branding Henri Michel, the former Les Bleus coach, a "bag of s***", while also copping suspensions with Olympique Marseille and Nimes for meltdowns. The talent was there. As was the profile. It was just a matter of Cantona finding himself the right club and the right manager.
For Ighalo, the better comparison is with his new manager. Solskjaer was a roll of the dice for the United board in the aftermath of Jose Mourinho's sacking. And much like his playing career, the Norwegian saw the opening and grabbed it with both hands.
And history could repeat itself with Ighalo. In one sense, Bosnich is right. Scrub out the Cantona reference and he's spot on: Ighalo has the opportunity of a lifetime - and with next-to-no expectations around him, he has nothing to lose. Score a few goals. Have the Stretford End sing your name. And Ighalo 'could do an Ole' and make it impossible for the United board not to extend this relationship into next season.
But it will still be as a short-term arrangement. An instant hit, with little long-term impact.
Ighalo has the potential of doing good things for United. Just as Grealish, as the player he is today, could do the same should he arrive in the summer. But neither of them are Eric Cantona.
The Frenchman's influence on what the club is today should never be flippantly voiced. Without Bill Fotherby's enquiry about Denis Irwin all those years ago, Manchester United, as a global institution, would not run close to what we see today.