Roberts' knock capped a miserable night for the Blues who saw their RaboDirect PRO12 play-off hopes all but snuffed out as the Warriors racked up a bonus point in their ruthless 31-3 victory.
The Wales centre went into the game with heavy strapping after initially hurting the same knee in the defeat of England and appears to have aggravated to same injury in the 54th minute.
That could cast into doubt his participation in the Blues' Heineken Cup clash against Leinster next week and coach Justin Burnell revealed: "I don't really know the full extent, but he had a bump on his knee.
"His knee was heavily strapped up so we'll have a full assessment of that by Monday morning."
In contrast to Burnell's concerns, Warriors coach Sean Lineen was ecstatic with the performance of his young centre Alex Dunbar.
While the 21-year-old did not cross the tryline himself, it was his breaks that led to scores from Chris Fusaro and Colin Shaw that secured a crucial bonus point in the Warriors' race for the top four.
With many of Glasgow's internationals returning after the Six Nations, many would have expected Dunbar and other youngsters to drop out of the starting XV but Lineen maintains his performance underlines the strength in depth the Warriors possess.
"Young Alex was absolutely fantastic out there," he said. "Guys like him underline the level of competition in the squad - everyone is being pushed and everyone is pushing.
"This was a massive win for us and these lads now have a chance to do something really special in the last few weeks of the campaign."
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