The 23-year old defender arrived at Selhurst Park from Huddersfield Town for £2million in the summer but is yet to feature for his new club after sustaining the injury in training.
But club physiotherapist Alex Manos suggests the highly-rated youngster is working well in training and is expected to figure in the coming months.
"Jack had a couple of complications, which have just resolved themselves and he's due to hopefully join in training towards the end of the week," Manos told the Croydon Advertiser.
"He's been keeping up his fitness work and it's just a case of getting a couple of good sessions under his belt out on the pitch, such as some positional-specific work.
"He's looking good and hopefully it won't be too long before he's back."
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