While pointing out the figures being suggested are no more than speculation, Stubbs revealed he was convinced from the moment he signed him for the Easter Road club four years ago that the midfielder was simply on another stepping stone in his career.
Already a League Cup winner with St Mirren, McGinn made a somewhat inauspicious start in a green-and-white shirt, a second half substitute as he replaced Scott Martin in a 2-1 defeat away to Dumbarton.
However, by the end of that season McGinn had not only won his first Scotland cap, named man of the match in a 1-0 win over Denmark, but had marked himself out as a Hibs legend, part the team that conjured up that stunning, historic Scottish Cup triumph.
A year later McGinn had very much been the driving force behind the Capital club taking the Championship title before marking their return to the top flight with a top-four finish and back into Europe.
McGinn starred in the first of those four Europa League matches, home and away against NSi Runavik and Asteras Tripolis, but by the time their tie with Norwegian side Molde – then bossed by now Man Utd manager Ole Gunnar Solskjaer – he was gone, Aston Villa having forked out a £3m fee for his signature.
It represented a terrific piece of business for Hibs, who had only spent an initial £100,000 and Saints who picked up a third of the sell-on fee.
But that sum was repaid almost immediately, McGinn helping fire them into the English Premier League – scoring what proved to be the winner in their promotion play-off against Derby County at Wembley – while becoming their player of the year.
“It’s no surprise,” insisted Stubbs of McGinn’s name being linked with that of Manchester United. “John has gone from strength to strength every time he has stepped up from club to club. His move from St Mirren to Hibs was what he needed and then in going from Hibs to Aston Villa he has really taken his game to another level and that’s all credit to him.”
Celtic had made a string of what were seen as derisory offers for McGinn before finally matching Villa’s bid but, by that time, any hope they had of signing him was already gone.
And that, believes Stubbs, was because he wasn’t “really Brendan Rodgers’ type of player. He said: “John’s not really a pretty or elegant player. He’s a bit of a rough diamond, a throw-back, the sort of player that’s missing from the game.
“There’s too many of those players who look the part rather than those who play the part.”
Playing on the bigger stage in England has undoubtedly brought McGinn greater attention in an environment where eight-figure sums are regularly traded, United having recently paid out £45m for Crystal Palace’s 21-year-old Aaron Wan-Bissaka.
Stubbs said: “To be honest, the figure is irrelevant, it’s only what someone is prepared to pay for a player.
“But what you can say is that John’s very much on an upward curve.”