Harlequins v Leinster, The Stoop, Tomorrow (KO 3.15) Live BTSport
There is luck, good luck and there is plain bad luck.
Leinster might want to take a punt on a witch doctor given the unbelievable damage they have had to absorb this season.
Ireland internationals Dave Kearney and Dominic Ryan have been the latest to pick up injuries serious enough to put them outside the 23-man squad for Sunday.
Of course, Fergus McFadden, a real live warrior in these matches, has been taken out by surgery to his thumb
This means coach Matt O'Connor has to put his faith in the remedy to Luke Fitzgerald's groin/hip injury on the left wing as Zane Kirchner is left to stew on the bench.
"I think these two weeks are going to be massive for us in defining the rest of our season," said full-back Rob Kearney.
"We know we need a big performance. The last couple of weeks haven't been the normal performances we would have liked."
This is a step-up from the workmanlike win over the PRO12 League leaders Ospreys last Saturday.
"Last week wasn't particularly good to watch. If we perform like that again this week we will probably struggle."
O'Connor was unrepentant abut the way Leinster have gone about their business this season.
They have had to deal with one broken player after another, while the relatively shallow Harlequins squad remains largely intact.
At openside alone, O'Connor is without Sean O'Brien, Shane Jennings and Dominic Ryan. This has forced his hand.
Flanker Jordi Murphy would want to make the same improvement from The Ospreys to Harlequins as he made from Treviso to the Welsh club last Saturday.
The multi-purpose back rower has had so little game time this season, totalling 122 minutes from those two matches.
In addition, Conor O'Shea has opted to include two poachers in the form of England captain Chris Robshaw and the excellent Luke Wallace.
Club captain Jo Marler is coming into this off a career best performance against Australia with stout second row support from Charlie Matthews and the reliable George Robson.
In an overall context, Leinster are in a hole they will have to dig themselves out of without Ireland forwards O'Brien, Cian Healy, Richardt Strauss, Jennings, Ryan and Marty Moore.
O'Connor is adamant that Leinster exploit weaknesses rather than ignore them.
"Our philosophy is finding a competitive advantage against the opposition to win the game. That's our style of rugby," he said.
The Australian is struggling to find the same respect at Leinster as he did at Leicester, certainly from a section of the club's supporters.
"I'm doing the same thing I was doing there," he said.
"We've got a Test pack on Sunday. What's your competitive advantage? That's the game."
Harlequins: M Brown; M Yarde, M Hopper, G Lowe, A Tikoirotuma; N Evans, D Care; J Marler (capt), D Ward, W Collier, C Matthews, G Robson, L Wallace, C Robshaw, N Easter.
Leinster: R Kearney; D Fanning, G D'Arcy, I Madigan, L Fitzgerald; J Gopperth, E Reddan; J McGrath, S Cronin, M Ross, D Toner, M McCarthy, R Ruddock, J Murphy, J Heaslip (capt).