The Manchester City captain helped the Belgian make a decision ahead of his Bhoys spell.
However, Denayer has no regrets and relished the physical side of his time in the Scottish Premiership.
The 20-year-old valued the experience he gained at Parkhead but says he was unsure of exactly what he could gain with the Scottish champions.
He is quoted as saying by the Mirror: "Before I went to Celtic I wanted to stay here [at City] but Celtic gave me a lot of experience and, when I came back, I decided I want to play here.
"The idea was to give me experience of a more physical game, and of playing in the first team. It didn’t come as a shock because before I went I watched a few Celtic games - I knew it would be physical."
But when it came to decision time, Denayer admits Manchester City skipper Vincent Kompany was extremely helpful: "He speaks to me a lot and gives me good advice. He is a good guy, like having a big brother. He just told me to do whatever was best for me."
An open door?
Such was Denayer's success at Celtic, of course, that if the Manchester City defender can't break into the first team at any point, Ronny Deila's door will no doubt be open to him at all times.
The Bhoys have brought Dedryck Boyata in as Denayer's successor but extra strength in depth will never hurt a club aiming to compete in at least the group stages of the Champions League.
And the 20-year-old's rapport with the Celtic fans should mean a return would always be welcomed by supporters. For now, though, the Belgian will undoubtedly give his Manchester City career his best shot...