O'Brien to make Champions move
Seán O'Brien will have anywhere between 60 and 80 minutes to show Leinster's head coach Leo Cullen he can be thrown straight back into the fire that is the Champions Cup semi-final.
'The Tullow Tank' has finally shaken off the shoulder problem that took longer than expected to heal to take his place on the openside against Benetton Treviso.
There is a strong argument to be made that O'Brien, in the whole of his health, is one Cullen can't leave out for The Scarlets and the double threat of Tadhg Beirne and James Davies.
"Em, it's very hard," responded the coach on the subject of whether a fit O'Brien is an automatic starter at this point in the season.
"We're very much focused on Treviso at this stage, and depending on what happens in this game we can make some assessments for the following week."
In years gone by, the 2017 British & Irish Lions first choice flanker would just slot straight in. The versatility of Scott Fardy and the form of Dan Leavy and Jordi Murphy, moving from number eight to blindside this evening, leaves that open to interpretation even with Josh van Der Flier out and a cloud hanging over Rhys Ruddock and Jack Conan.
However, O'Brien, fit and firing, is still something to behold, especially in the big game atmosphere that will pour down from the stands of the Aviva Stadium next Saturday afternoon.
"For him, it is just the presence that he brings," said Cullen about what his former team-mate had to offer.
"He is a great voice in the dressing-room. He is a great voice defensively in the line because he's so strong in around that ruck area," he added.
"He gives us really strong defensive presence.
"Then, on the other side of the game, it is just the intent with which he carries and his presence in all the physical components of the game."
O'Brien just has to do what he has always done.