Duffus is currently recovering from knee surgery and is targeting a return to action with the U21s in September.
The 19-year-old came close to make his debut from the bench for Roberto Martinez’s side in the Europa League against Young Boys in February.
Everton were leading 4-1 thanks to a Romelu Lukaku hat-trick with 30 minutes left to play in Bern when Duffus was given the nod to get ready.
However, only moments later Everton defender John Stones was shown a straight red card for bringing down striker Guillaume Hoarau which forced a rethink from Martinez.
“The physio nudged me and said Lukaku had a tight hamstring so I was told to go and warm up,” Duffus recalled on Everton’s website.
“Obviously you can imagine how I felt – I was buzzing thinking I was going to come on.
“But unfortunately John Stones got sent off about two minutes after that, so things changed.
“I was just made up to be there to be honest. Hopefully I can pick up where I left off when I get back fit and be challenging to get in that first team again.”