Reports that Seán O'Brien will be in Nice today for Toulon's game at home to Cardiff could not be verified last night but in any event Leinster continue to life live without their human wrecking ball for their hugely important, penultimate pool game Castres tomorrow.

As a curious aside, the Carlow GAA senior football team confirmed yesterday O’Brien will be joining their backroom staff, in an unspecified role as motivator-cum-training and dietary adviser. The county chairman Michael Meaney said O’Brien’s involvement with the squad is expected to last for the four or five months he is recovering from a shoulder operation.

O'Brien also missed the home defeat to Northampton. The side will again be led by Jamie Heaslip, the other high profile subject of transfer speculation. In effect, Matt O'Connor has made three changes from the side that faced Northampton, with Jimmy Gopperth's impressive performance off the bench last weekend against Connacht earning him the nod ahead of Ian Madigan.

In the backrow, Rhys Ruddock has failed to recover from the calf injury suffered in the second half of the game in the Sportsground and Kevin McLaughlin is restored after a recent lay off with a thumb injury. The other change from that line-up sees Jordi Murphy retained from last week at openside, with Shane Jennings on the bench.

This also means Dave Kearney is chosen ahead of Zane Kirchner while Luke Fitzgerald, one of Leinster's most impressive performers in both Northampton games, is recalled after missing out last week due to illness. Rob Kearney will make his 50th Heineken Cup appearance, thereby emulating Gordon D'Arcy, Leo Cullen, Shane Horgan, Brian O'Driscoll and Malcolm O'Kelly.

Restored
Mike Ross and Mike McCarthy are also unsurprisingly restored to the tight five, with O'Connor and the Leinster think-tank understandingly placing huge significance on the set scrum. The scrum, and line-out maul, are the bedrocks for much of Castres' year-plus unbeaten record, and along with their defence, helped them to a first Top 14 title in 20 years last season.

Regardless of whether they still believe they can advance themselves, Castres are sure to defend their home record with characteristic French fervour, all the more so as Leinster are such prized scalps, and the inches gained or lost in the scrum could have a seismic effect on the match.

In Leinster’s hard-pressed win at the RDS last October, it was a bizarre sequence of crooked scrum feeds by Castres that led to the pivotal sin-binning of reserve scrumhalf Julien Tomas which swung the game.

Tomas reverts to the bench again in one of three changes to the backline, while Yannick Forrestier is restored in one of five changes up front, while other members of the French squad, fullback Bruce Dulin and outhalf Remy Tales are retained. This would appear to be a signal of their intent but their influential South African-born pair of Rory Kockott and Antonie Claassen remain sidelined with calf and knee injuries.

Former Springboks and Ulster number eight Pedrie Wannenburg also misses the clash due to a thigh problem while fullback-cum-winger Geoffrey Palis, who on Monday was called up to the France pre-Six Nations training camp, is out with a dislocated thumb.

Qualification
Leinster could conceivably secure qualification for the knock-out stages for the 10th time in 13 years – and thereby atone for last season's lapse after three victories and a semi-final in the previous four years – were they to win in Castres tomorrow and Northampton to slip up away to the Ospreys.

However, in the probability that Northampton – revived after their win in the Aviva and with more to play for than the Ospreys – stay in touch, then Leinster need to win in the Stade Pierre-Antoine in readiness for the cruelly-scheduled pool finale at home to their Ospreys’ bugbears next Friday night.

Ultimately, their destiny remains in their own hands and two wins will ensure a quarter-final place in April and thereby give full meaning to the remainder of their season. Besides which, if they are to target a favourable and financially rewarding home quarter-final, two wins with a bonus point or two are imperative.

If the Leinster scrum holds up and they can negate the Castres maul they should be much of the way there, and if Heaslip, Murphy, McLaughlin and co make the hard yards, the clearing out is effective, then the have the sharper firepower. It is perhaps helpful that the forecast is fine and that a strong referee Nigel Owens is unlikely to be cowed by a hostile French crowd who will presumably bay for every decision.