The All Black star, 31, damaged his knee cap during pre-season training and has completed just 40 minutes this season.
But Blues coach Dai Young insists his talismanic number eight will be fighting fit ready for the crunch European tie with Gloucester in two weeks time.
Young said: “Xavier is back in training and should be pushing for some involvement in the Leinster game.
“Then hopefully he will be ready for selection for the Heineken Cup games. We’ve done well without him but there is no doubt he will give the squad a massive lift.”
