THE scramble is on to impress coach Joe Schmidt as the Ireland World Cup players start to mix it up with the men who have kept Leinster's PRO12 League campaign on track.
For all the chat about the integration of new signings and the improvement of a new generation of players, there are, perhaps, not many issues for Schmidt about which side will start round one of the Heineken Cup with what could be a treacherous trip to Montpellier.
There are decisions to be made about who will combine with captain Leo Cullen at lock. Steven Sykes and Devin Toner are ahead of Damien Browne on that front.
At scrum-half, Eoin Reddan and Isaac Boss will probably interchange throughout the season as they did last term. Jamie Hagan, Rhys Ruddock and Dominic Ryan have not done enough to force their issues just yet.
Here are three key duels that could last the length of the season.
SEAN CRONIN v RICHARDT STRAUSS
Ireland's second-choice hooker will start the season in the same predicament for Leinster. He has made a brave move from Connacht to further his international prospects and win trophies.
"I'm bringing back huge motivation, anyway. It's huge motivation to be coming back after being involved in a competition like that," said Cronin.
"It's the same as coming out of the autumn internationals or the Six Nations, especially when you get limited game time. You're champing at the bit to get back in."
Cronin knows he will have to battle it out with a player who will be available to play for Ireland next season, under the three-year residency rule.
"Yeah, it's going to be extremely tough. I thought he (Strauss) did tremendous here last year. It can only benefit you against a player like him," said Cronin.
"I think at every top European side they have at least two really good players in each position, and I hope what's going to happen now is that we're going to drive each other on for the rest of the season."
ROB KEARNEY v ISA NACEWA
Ireland full-back Kearney roared back from the most serious injury of his career to show, once again, his big game temperament against Australia, Italy and Wales. He looks as good as new.
Moreover, time away from the game gave the Carlingford man food for thought about how much he loves the sport in which he became a world star from his performances for the British & Irish Lions in Tests II and III in South Africa in 2009.
Nacewa (pictured right) plays the part of Mr Consistency from a variety of positions in the three-quarter line, taking on the kicking chores in the absence of Jonathan Sexton to notch up 70 points in the first six matches.
The greater versatility of the New Zealander makes it very likely that he will make the move to right wing for the Munster game. This will give him the freedom to pop up in midfield from Leinster's set moves.
It would also remove former Connacht flyer Fionn Carr from the right wing and into a head-to-head contest with Luke Fitzgerald for the left wing, which Schmidt sees as Fitzgerald's best position.
GORDON D'ARCY v FERGUS McFADDEN
This is not the first crossroads the 31-year-old D'Arcy has faced, as monsters like Jamie Roberts and Ma'a Nonu roamed the midfield at the World Cup. It has always been thus.
The O'Driscoll-D'Arcy partnership has survived on wit and intelligence more than size and strength, and D'Arcy was not entirely at fault for the Mike Phillips try in the quarter-final. But he can take to heart what should be left on the pitch.
For McFadden (pictured right), the burst of excitement out of making the Ireland World Cup squad must have been replaced by the gradual deflation of not making any real impact on the field.
At the end of last season, there was a case for believing McFadden was on the heels of D'Arcy for the right to partner O'Driscoll. But a brief stint on the wing put him in limbo.
Then, he was limited to one match against Russia at the World Cup -- an 80-minute return for a hellish pre-season and six weeks in New Zealand. He will look for greater backing from his club coach than he got from his national management.