The Derry born defender has admitted that he is patiently waiting for his chance of first team football with the Toffees after making a breakthrough last season
The 20-year-old centre back made his Premier League debut for the Toffees in January 2012 after enjoying a spell on loan at Scunthorpe and despite making only one senior appearance this season, he says that he must be ready.
"If any of the defenders get injured, I have to be ready. My aim when I am playing [with the U21s] is to show that I can step up higher and if one of them gets injured that the manager can put me in," Duffy told evertonfc.com.
He continued: "Obviously when I got into the team in January last year I was nervous - I had just come from League One football - but since then I've been around the team, training, getting to know them and them getting to know me as a player.
"I played nearly every game in pre-season and I feel like I am getting better, getting more mature and I am enjoying football at the minute."
The Republic of Ireland under-21 international made his Everton debut at the age of 17, coming on as a substitute for Sylvain Distin in a 1-0 victory over AEK Athens in the Europa League and he revealed that his manager, David Moyes, impressed upon him the importance of having patience as he progresses as a footballer.
"The manager reminds me that there are not many 20-year-old centre backs playing in the Premier League and that I have got to be patient, which I am.
"I am just enjoying being at this club to be honest and it is a dream to even be near the first team. So I am just being patient, working hard every day in training and hopefully I will get in the team some day," concluded the defender.