Cullen motto is 'no fear'
Centres Reid and McFadden will start together for just the third time
Leo Cullen is a curious one. The Leinster coach sees opportunity where others see a reason to be fearful.
Who knew the cool-headed captain would be such a risk-taker?
The decision to blend Noel Reid and Fergus McFadden into his midfield tomorrow demonstrates his fearlessness.
Why? Well, where Gordon D'Arcy and Brian O'Driscoll revelled in a symbiotic relationship honed over years of working in tandem, Reid and McFadden have to replicate the chemistry they have shown in practice the only place it matters - on game day.
"We look at different combinations the whole time and different strengths and weaknesses of everybody," said the coach.
"This is the combination we have gone for.
"Ferg is very robust, whether that is defensively or in the carry and, depending on the conditions as well, we need the strong carry that he gives us."
Reid and McFadden have started together in the centre just twice in back-to-back PRO12 wins over Glasgow Warriors (28-25) and Zebre (27-0) in March 2014.
"They have trained plenty though over the last couple of weeks. Even during that World Cup period Ferg would have done plenty in training at centre."
Okay, Luke Fitzgerald and Ben Te'o have been hurt by injury and natural 13 Garry Ringrose is on the bench.
There was the option to move Zane Kirchner inside or insert Ian Madigan at 12.
"Just for this game, I thought Ferg brings real experience," said Cullen.
"He has been great for us so far and he just brings a real toughness into the centre there."
There is a balance between the wit and width of playmaking Reid and the direct, honest work of McFadden.
"Noel has performed really well during this whole period and back into the pre-season games," he emphasised. "He gives us a good bit of solidity in what the team is trying to do because he has been in the system pretty much from day one.
"He was involved with the very early Ireland camps.
"But since Noel has come back he has given the team really good voice."
When it comes to putting runners into space, Reid has few equals in Ireland.
When it comes to the heavy duty of defence, he has yet to totally convince.
This is the time to step up and lower his shoulder into Wasps' hard-chargers in a way he didn't do against the Scarlets' Hadleigh Parkes last week.
"I'm looking forward to seeing Noel play because he has had a really good gradual improvement in his level of performance week to week.
"He gives us some real consistency through the message he drives even if he hasn't played a huge amount with Johnny (Sexton)."
In fact, the former schoolboy out-half played there twice before he was seen as a better fit at inside centre where his sweet passing skills could be put to best use.
He has seen eight different partners come and go at centre through his 30 starts in the position, namely D'Arcy, O'Driscoll, Collie O'Shea, Ringrose, Fitzgerald, Te'o, McFadden and current Wasp Brendan Macken.
This is not fair grounds for assessment. He needs time to bed-in and build a relationship with someone.
Just when it looked like Reid and Te'o were developing an understanding with one another, the explosive New Zealander shipped an injury against the Scarlets.
Enter McFadden. The problem is Te'o (glute) and Fitzgerald (neck) could be back to work next week.
"We had 20 guys come back into the system two weeks ago so there are a lot of combinations that aren't going to be perfect," he heeded. "We hope we will get improvements as the tournament goes on because we have worked closely with some and not with others because of the World Cup.
"There has to be a certain sense of reality as well. We are building in a certain direction and it is almost like when everyone comes back in you have to take a good few steps back to the foundation level so you can start building again and that can be frustrating."
For sure, Wasps have been able to generate a flow between possible England international Elliot Daly and Ben Jacobs.
They were more than adequate against Gloucester in the Premiership last Sunday.
Where Wasps have the momentum of time together, Leinster have the benefit of winning interrupted by the change of personnel.
"As coaches you think you are going in a certain direction and then you have to take a few pretty significant steps back.
"That has been a challenge but we knew it was going to be like that."
Leinster: I Nacewa (capt); Z Kirchner, F McFadden, N Reid, D Kearney; J Sexton; E Reddan; J McGrath, R Strauss, M Ross, D Toner, M McCarthy, J Murphy, S O'Brien, J Heaslip.
Wasps: C Piutau; C Wade, E Daly, B Jacobs, F Halai; R Jackson, J Simpson; M Mullan (capt), C Festuccia, J Cooper-Whoolley, J Launchbury, B Davies, S Jones, G Smith, N Hughes.