O'Connor faces fitness concerns for French trip
Rhys Ruddock and Aaron Dundon have emerged as injury doubts for Leinster ahead of Sunday's visit to Castres, but the province remain hopeful that both will recover in time for the crucial Pool 1 clash.
Flanker Ruddock damaged his calf during the win over Connacht last weekend and will be hoping that the knock is not bad enough to break his run of games and form, while reserve hooker Dundon has a shoulder injury.
Kevin McLaughlin is on standby should the blindside not recover, and with a five-day turnaround before the final pool game against the Ospreys, coach Matt O'Connor may look to keep Ruddock on ice so that he's fresh for the visit of the Welsh region.
There was better news for the Australian concerning veteran duo Shane Jennings and Leo Cullen's return to training, while Luke Fitzgerald should overcome his flu to take part at the weekend.
Fergus McFadden could be fit in time to take some part in the Ospreys game having had the screws in his arm removed, but Cian Healy remains some way away from a full return and Sean O'Brien underwent an operation on his shoulder at the end of last week and is now beginning his long road back to fitness.
Out-half Jimmy Gopperth is the favourite to get the nod for the No 10 jersey ahead of Ian Madigan and he believes that the success of the province's season depends on the next two weeks.
"This will define our season," Gopperth said. "We want to be in the last eight of the Heineken Cup. Castres are unbeaten at home throughout every competition they have played in, so it's a pretty big fortress for them. We have to make sure that we are on top of our game to go down there and get a result.
"Everyone knows they are a pretty physical bunch. They have got a massive pack, but their backs also love to offload. They love creating opportunities and if you kick poor against them, or if your kick-chase is poor, they will make you pay.
"We have got to make sure our basics are done well and we put pressure on them a lot in the right areas of the field."
* Uncapped fly-half Jules Plisson has dislodged experienced playmakers Francois Trinh-Duc and Frederic Michalak from France's RBS Six Nations squad.
The 22-year-old outside-half is one of three developing Stade Francais stars to muscle into Phillipe Saint-Andre's squad for next month's European tournament.
Flanker Antoine Burban and full-back Hugo Bonneval join team-mate Plisson in Saint Andre's line-up, while Castres full-back Geoffrey Palis in included for the first time.
Stade's resurgence is underscored by their climb to second in the Top 14 rankings, with Plisson holding his own alongside decorated Springbok fly-half and team-mate Morne Steyn.
France kick off their Six Nations charge by hosting England at Stade de France on February 1.
France Six Nations squad: T Domingo (Clermont), Y Forestier (Castres), B Kayser (Clermont), D Szarzewski (Racing-Metro), N Mas (Montpellier), R Slimani, A Flanquart (both Stade Francais), Y Maestri (Toulouse), P Pape (Stade Francais), S Vahaamahina (Perpignan), A Burban (Stade Francais), T Dusautoir (Toulouse, capt), B Le Roux (Racing-Metro), Y Nyanga (Toulouse), D Chouly (Clermont), L Picamoles, J-M Doussain (both Toulouse), M Machenaud (Racing-Metro), J Plisson (Stade Francais), R Tales (Castres), M Bastareaud (Toulon), G Fickou (Toulouse), W Fofana (Clermont), M Mermoz (Toulon), S Guitoune (Perpignan), Y Huget, M Medard (both Toulouse), G Palis (Castres), H Bonneval (Stade Francais), B Dulin (Castres).