Ally McCoist believes JJ Gabriel's decision to seek a move away from Manchester United will have an alarming domino effect.
Gabriel, 15, sparked headlines on Tuesday when it emerged he asked to leave the Red Devils.
What is the latest on JJ Gabriel's future?
talkSPORT understands Real Madrid are now leading the race for the teen sensation's signature but face competition from Barcelona and two Premier League clubs.
Despite Gabriel's desire for a new challenge, the Red Devils remain hopeful of rectifying the situation.
Should Gabriel depart, it would deprive United of yet another top English talent.
The Red Devils have historically been synonymous with producing elite homegrown players and also prising them away from other clubs.
But that trend has slowly regressed in recent years, with the likes of Elliot Anderson, Morgan Rogers and Declan Rice all spurning United's advances over the years.
Ally McCoist reacts to JJ Gabriel's exit demand
It's why McCoist fears the Red Devils losing Gabriel could have long-term ramifications in the transfer market.
"The fact of the matter is, top players in world football now will choose other clubs before Manchester United because they've got a better chance of winning," McCoist said on talkSPORT Breakfast.
Over the last nine seasons, the Red Devils have won just two major trophies.
Additionally, United have finished in the top four of the Premier League only six times since they last won the competition, which was in 2013.
All signs point to a club that is far removed from its glory days.
It was hoped that Gabriel, who has been dubbed the 'kid Messi', would eventually play a significant role in reversing United's malaise of late.
But those aspirations now appear to be dashed, with Gabriel's father, a former Republic of Ireland international, believed to be playing a driving role in the controversy.
Alex Crook's verdict on the latest JJ Gabriel developments
McCoist's fears about how damaging Gabriel's exit could be to United's future transfer dealings was echoed by talkSPORT's chief football correspondent Alex Crook.
"I think optically it's a really bad look if Manchester United lose somebody who Ryan Giggs has gone on record as saying he's a generational talent," Crook said on talkSPORT Breakfast.
"Particularly if he was to join another English club, it probably tells you where United are at in terms of pulling power."
Gabriel was due to be named in United's matchday squad for their Carabao Cup third round clash against Brighton on Wednesday evening, live on talkSPORT.
But the latest developments have plunged his potential inclusion into doubt.
Should Gabriel take the field, he will become United's youngest-ever player.
Goalkeeper David Gaskell is the incumbent record holder after he played his first game aged 16 years and 19 days.