Roberts hobbled off with what appeared to be a reoccurrence of the knee injury he suffered in the Six Nations in the second-half in Glasgow.
It was a disappointing night all round for the Blues, who could only manage three-points as Glasgow claimed a bonus-point triumph.
The Blues demonstrated plenty of early promise at Firhill but it was Glasgow that enjoyed the first real opportunity.
Following a sustained period in pressure, in which the Blues scrum fell foul of the law on several occasions, Stuart Hogg created an opening for Colin Shaw.
But the wing failed to hang onto the Scotland starlet’s pass and the chance went begging.
But it did not take the hosts long and Ryan Wilson powered over to score between the sticks. Duncan Weir was on target
Glasgow should have grabbed a second try on the half-hour mark but Chris Fusuro was guilty of ignoring the overlap and they instead has to settle for a penalty.
Leigh Halfpenny was off target with a difficult penalty attempt on 38 minutes as the scores remained 10-0 at the interval.
Wilson grabbed his second try after just four minutes of the restart after Wilson crashed through Leigh Halfpenny from close-range.
Weir converted before Halfpenny hit back with the Blues first points. But the visitors were dealt a major blow when Roberts limped off.
Matters were made worse when Fusaro raced clear and Shaw rubbed salt into the Blues’ wounds with a break-away bonus-point try in the dying minutes.
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