David Holwell remains in the Leinster squad ahead of the visit on Friday of European Cup opponents Castres, but the responsibility is on the shoulders of Jonathan Sexton as the team looks to negotiate tricky back-to-back fixtures without some key decision makers.

The absence of Felipe Contepomi and Isa Nacewa through injury forced Michael Cheika to recall Holwell from the wilderness prior to last weekend's Magners League win over the Dragons, but the coach insists Sexton is still the man he is relying on at outhalf.

Sexton, he added, is a 'team player' and is working with, rather than competing against, Holwell ahead of a crucial week.

"Felipe (Contepomi) is a big loss as are Isa (Nacewa) and Gordon D'Arcy," said Cheika today. "Every year we have a bit more depth and we can manage situations and it will take some managing. There's a lot of responsibility on (Jonathan) Sexton and an importance on David (Holwell) to be prepared in terms of game knowledge if he's called upon.

"Jonny is competing against the other two boys," Cheika added. "Dave has come as back up and he understands the situation.

"If anything, they're working a lot together because Jonny has to fill him full of information and Dave has a lot of experience that he will be able to pass on in the short time that he is here. Jonny is a member of the team and if he was to get injured he would want his coach to be preparing a back-up plan."

Cheika will be relieved to have Brian O'Driscoll available after he picked up a shoulder injury against the Dragons, while Rob Kearney, Luke Fitzgerald and Jamie Heaslip return to the squad after being rested at the weekend.

Eoin O'Malley, Felix Jones, Paul O'Donohoe and Fergus McFadden are left out, but the latter, in particular, was close to the squad after impressing on Saturda.

"There definitely was a temptation to put Fergus in because he played very well at the weekend, but we want him to find his feet because he still has other building blocks to be earned.

Shane Jennings is included but Cheika still rates him as "50-50" after the flanker sat out training today.

Two bonus point wins have left Leinster with a six point lead over Wasps and Edinburgh in Pool 2, while Castres are fourth on one point, but Cheika has seen first hand how tricky double-headers can be and is not underestimating the task at the RDS or at the Stade Pierre-Antoine on December 12th.

"We've had some good experiences on back-to-back (games) and we've had some bad experiences in my time here," said the Australian. "So we've got to make sure - like we said before the first game of the first block of European matches - that we win the two games in a row.

"We have now managed that three times out of nine and we will take each of these games as individual challenges so that we can try to make it the fourth time."

Leinster squad

Forwards (14):Cian Healy, Brian Blaney, Bernard Jackman, CJ van der Linde, Stan Wright, Trevor Hogan, Devin Toner, Malcolm O'Kelly, Rocky Elsom, Cameron Jowitt, Shane Jennings, Sean O'Brien, Jamie Heaslip, Stephen Keogh

Backs (10):Chris Keane, Chris Whitaker, David Holwell, Jonathan Sexton, Simon Keogh, Luke Fitzgerald, Brian O'Driscoll, Shane Horgan, Girvan Dempsey, Rob Kearney