The 27-year-old Irish outside half hadn't played since injuring his hamstring in the RBS 6 Nations defeat against England. That injury cleared up, but he tore a tendon in his foot in the Captain's Run ahead of the final championship match against Italy in Rome.
A three time Heineken Cup winner with Leinster, Sexton averages 18 points from his three finals in 2009, 2011 and 2012. That big game temperament could be crucial in the battle of the two European champions from 2012 at the weekend.
Leinster warmed-up for the clash with the reigning Amlin Challenge Cup champions with a five-try, 41-22 win over Zebre in Italy to stay on course for a home Play-Off in the RaboDirect PRO12. Victory moved them into second place, three points behind Ulster Rugby.