After initially picking up the injury on the 2009 Lions tour, Roberts played through last season with the injury before the full extent was diagnosed.
Whilst he is likely to miss the festive period fixtures against the Dragons at Rodney Parade and the visit of Magners League champions the Ospreys, a return for Round 13 is possible.
"Jamie's comeback won't be too long after Christmas," said Young.
"He's getting there and has another appointment with the specialist in a couple of weeks. We will then pinpoint a game for him to return."
The Blues travel to Thomond Park to face current league leaders Munster on Saturday. The kick off time in Ireland has been revised to 17:00hrs.
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