The teenage sensation has been told he definitely does need an ACL op and won't be back in action until late next year.

He fell awkwardly during his Celtic debut just 20 minutes after coming off the bench and was stretchered off the ground in the 5-0 win over Dundee last week.

His knee was so badly swollen, medics were struggling to make an accurate diagnosis.But this morning, Arzani, 19, took to Instagram to confirm his season is over already.

"I received the bad news today that I will indeed need an ACL Op ruling me out until next season," he said.

"Apologies to the Celtic fans for my 20 minute cameo 😅 This is however the beginning of my journey and I promise to be back better than ever. Day 1 road to recovery starts now."

He added: "Thank you to everyone who has taken the time out of their day to show support and love.

"I’m trying my best to reply to everyone but please understand this is also a very tough time for me."

Arzani is on loan to Celtic from Manchester City who snapped him up from Melbourne City after the World Cup where he lit up the Socceroos in his cameo appearances.

He is likely now to return to Australia after surgery and his future at Celtic is uncertain. His loan deal is for two years so could still rejoin them next season, depending on how his post-op rehab progresses.

But he will definitely miss this January's Asian Cup campaign as Australia aim to defend their 2015 crown.

In a separate video posted as an Instagram story earlier today, Arzani appears to be in Barcelona. His knee can be briefly seen in a metal brace in the back of a chauffeur-driven car which appears to be a high-end Maybach luxury limousine.