So when one did at Celtic Park, he rushed to jump through.
Now the 19-year-old Belgian central defender is in a hurry to use the stage provided by the Hoops to show City boss Manuel Pellegrini he is ready to be called back at the end of his season-long loan and able to fight for a first-team place.
That will pitch Denayer in against the likes of countryman and captain Vincent Kompany, Martin Demichelis, and the man who has just been signed for £30million, Eliaquim Mangala.
But, with the exuberance and confidence of youth, he is up for the challenge - which is good news for his adopted club Celtic.
Denayer said: "It was not the plan at the beginning for me to join another club on loan. I wanted to become part of the Manchester City team.
"But the transfer window is open, this opportunity came up, and I thought it would be better to come to Celtic.
"City have just signed Eliaquim Mangala for £30m. And when a club spends that kind of money, they can't put him on the bench.
"Martin Demichelis is also there, a player who played in the final of the World Cup. He also needs to play.
"Vincent Kompany is the captain and he needs also to play, so it was going to be difficult for me."
Despite his tender years, Denayer clearly has an old head on his shoulders.
It allows him to plan for what is tipped to be a very successful career, with Deila already attaching a £10m-plus tag on him.
"I can't say what will happen in the future, but I want to show I can play in the first team for City," said the kid who was part of the side which played against Dundee in pre-season, a match taken in by Deila.
"I asked to go on loan, and Celtic were the club who gave me the most assurances to play.
"When I spoke with the manager, he told me he was going to give me my chance. So, when I get my chance, it is up to me.
"I need to play well and show him I can play. I'm fast, strong and I try to play football the right way. I don't just kick the ball away."
That could be a description of his mentor, Kompany. And Denayer is quick to pay tribute to his influence since he joined City
"I've learned a lot from him, because he is a good guy off the pitch," acknowledged the teenager.
"He talks a lot with me, so he helps me a lot. But I don't want to be the same as Vincent Kompany.
"Maybe the same career, but not the same player because I want to have my own style."