The 22-year-old was injured during Wales' final autumn Test against Australia following a sickening collision with Wallabies captain Stirling Mortlock.
Roberts played on for 15 minutes, not realising the extent of his injury, helping to create a try for wing Shane Williams as Wales triumphed 21-18.
Initial estimates by the Wales medical staff were that Roberts could return by mid-January, and he is now firmly on course to be part of coach Warren Gatland's plans for the RBS 6 Nations opener against Scotland at Murrayfield on February 8.
Williams, meanwhile, returns to the Ospreys line-up for tomorrow night's Liberty Stadium clash against Munster after recovering from a shoulder injury.
The Ospreys star has been sidelined since mid-December, missing three Magners League fixtures over the Christmas period.