He is not the only young player in recent times to have shown promise at one of the big Glasgow clubs but found making the breakthrough to become an established presence a different matter altogether.
Many a youthful aspirant has found their ambitions derailed on the ultimate of catch 22 situations: to show they are good enough they need a run of games in the side, but to merit selection every week they need to show they can perform consistently. Little surprise so few progress to become settled figures at either Old Firm club.
There are exceptions, of course. After a difficult start, Alan Hutton went on to excel at Rangers and was sold to Tottenham Hotspur for around £9m while, across the city, Celtic had Aiden McGeady, whose steady performances caught the eye of Spartak Moscow who then paid a similar amount to take him to Russia.
Now there is James Forrest, another who has successfully bridged the gap between youth-team hopeful and first-team regular and who is now being linked with a move away from Celtic. Spurs, again, have been credited with an interest, despite the London club's manager, Harry Redknapp, dismissing talk of an imminent move for the player on Sunday evening. Other suitors will likely follow should he continue to excel as he has done for most of the season.
McGowan revealed that Neil Lennon, the Celtic manager, has been a fan of Forrest for quite some time, stemming back from their days together when Lennon was in charge of the reserve team and his young protege from Prestwick was just starting to make a name for himself. Lennon's graduation to the role of first-team manager, after Tony Mowbray's hasty departure, led to Forrest being fast-tracked into the side at the end of a forgettable 2009/10 season for Celtic, scoring on his debut. He was still only 18 years old at the time.
The following season, Forrest – with Lennon now in place as permanent manager – continued to grow in stature. He was often used as a substitute, and missed several months with an ankle injury, but his mentor stuck by him throughout it all.
It is difficult to say with any certainty whether Forrest has subsequently blossomed into a regular Celtic starter and Scotland internationalist as a result of Lennon's patience and tolerance, or whether his talent as an entertaining and effective wide player means he would have broken through in any case.
Perhaps being free of self-doubt or insecurities, as a result of his manager's unwavering backing, has allowed Forrest to express himself without worrying about the consequences.
"You just knew Neil liked James and he's blossomed into a top player, probably the first name on Celtic's team sheet," added McGowan. "If you'd asked someone a year ago if that would be the case, they'd have said no."
How much longer Celtic can hang on to him, however, is another matter. They are not a club in desperate need for money, but every player has a price and even Celtic may find the kind of sums being talked about hard to turn down.
In person, Forrest comes across as an uncomplicated, grounded 20-year-old and perhaps the prospect of moving away from Glasgow at this phase in his career holds little attraction. He may also look at the form of Spurs this season and wonder where he would fit into Redknapp's plans. Could he displace someone like Aaron Lennon when seasoned internationals like Niko Kranjcar and Steven Pienaar struggle to get a game?
Perhaps not at this juncture, although there is little reason to limit his aspirations should he continue to progress and develop at such an astonishing rate. If Charlie Adam can become a regular mainstay of the Liverpool team, then Forrest could surely, eventually, do something similar at Spurs. For now, though, he has few plans beyond trying to help Celtic to their first league title in four years.
"It is obviously good to hear, but it doesn't bother me," was Forrest's reaction to news of Spurs' reported interest. "The main thing is to keep playing well for Celtic. I'm not thinking about [playing in the Barclays Premier League]. We've still got the second half of the season to go with Celtic.
"We want to win the league, and the two cups as well, and that's all I'm thinking about."