When is the right time to promote a young player to a more senior team?
It is a question coaches cannot ignore.
Keep a player within their comfort zone for too long and you risk slowing development or regression.
Promote them too soon and you can damage the flow, scarring or scaring the player as they make their way.
Judged right however and the benefits to playing up are huge – increased experience, accelerated learning, confidence through achievement, the fostering of competitivity and self-realisation, an enhanced awareness of self.
But get it wrong and the inverse is true.
The dangers can be physical and psychological.
Taking the best from one age group and placing them in an environment where they will have to prove themselves all over again and possibly take on a new role is a challenge that some never recover from.
Small fish have to swim faster and think quicker when they are with the big fish.
Manchester United pushed Marcus Rashford early. They placed him in their residential
His progress has been incredibly quick but it was not always so. Rashford has jumped several levels this season but his progress through the United youth ranks has had occasional spells of turbulence.
As former United youth coach Paul McGuiness explained to the BBC:
“One of Marcus’ first games for the Under-18s was at Newcastle. He was on the wing and he was running and running. Even in the first half, his body language was screaming ‘Oh god, I didn’t realise I had to do this much’. It was crying out for him to come off. We kept him on.
“He was 16 in an underdeveloped body playing under-18 football. You have no idea how much the extra intensity takes out of you.”
At the start of the 2015/2016 season Rashford was quite far down the list of England youth prospects.
The coaches knew who he was of course but players such as the Chelsea trio of Dominic Solanke, Isaiah Brown and Tammy Abraham were all thought to be further ahead.
Now Rashford has jumped four international age groups and is reaping the benefits.
He has taken his chance.
The youngest player at EURO 2016 shows what can happen when talent is offered a chance and promoted with care.
But one of his United teammates shows what can happen if momentum is not maintained.
Rewind two years and Adnan Januzaj was the young star who had enjoyed a fantasty first Premier League season.
The one shining star in David Moyes’ Old Trafford reign was getting ready to play in the World Cup with Belgium.
His decision to declare for the nation of his birth caused much controversy with Albania, Kosovo, Turkey and even England failing to entice him.
But with hindsight Januzaj’s star had already begun to wane.
He failed to impress Moyes’ replacement and after a failed loan spell at Borussia Dortmund stands at a crossroads in his career.
Januzaj is only 21, has he peaked already?
Did United and Belgium push him too soon?
A lull is always likely with young players. It is how these dips in form are processed and learned from that is important.
Coaches must never push too hard. But when the pressure is on it is not always easy to think with clarity.
Sometimes players need to rest or take a step back before they can move forward again.
If handled correctly Rashford will continue to grow and his progress will not slow.
Handled correctly Januzaj will surely come again.
Jose Mourinho has the fate of two very interesting players to consider as he begins his life as Manchester United manager. Can he align them both? Or will one continue to soar while the other fades?
All coaches must take care when promoting talent.
The rewards can be just as big as the pitfalls.