However, it remains to be seen if he will be able to play in next Saturday's game against Saracens. A decision on his availability for the Wembley encounter will be made later this week.
Speaking on Monday, Leinster assistant coach Jono Gibbes said: "Brian had a scan and that revealed a more positive outlook than we expected.
"It's still not a definitive answer but we'll let it settle down over the next couple of days and get a clearer idea at the end of the week. The positive thing is that he hasn't been definitively ruled out."
Meanwhile, shoulder injury victim Leo Cullen has stepped up his rehabilitation and it is hoped that the Leinster captain will be available for selection this weekend.
Shaun Berne, who has an Achilles injury, continues to progress with his rehabilitation, though his return to action is several weeks away.