Young, outstanding in his new sweeper's role in recent weeks, has suffered discomfort since he first picked up the foot problem against West Ham back in September.
The 21-year-old was in pain again after Sunday's excellent performance against Liverpool and further scans on Monday confirmed his worse fear - a fracture.
He will now spend three weeks in a cast before hopefully getting the green light to resume training again.
"I went to the hospital on Monday and basically had a different scan to what I'd had before and it showed a fracture," he revealed. "I've not been 100 per cent with it and this has proved that I've been struggling.
"It's just disappointing because I've had a little run in the side and to get injured is just my luck at the moment.
"I knew it wasn't right. I've been struggling with it even in training but I've managed to get through games okay. I suppose the main thing is that I've found it now and it will be better to put it right than to continue playing on it.
"I'll be in plaster for three weeks and then I'll have another scan that will hopefully show it's healed up. Then I'll be able to train again.
"It hasn't sunk in to be honest. It won't be until I see the lads play Leicester on Saturday that I'll get the hump."
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Luke Young is out for at least a month after scans revealed a fracture in his right foot.