For the second successive season, Luke McGrath will miss the Six Nations through injury and the luckless scrum-half's knee ligament problem has ramifications for club and country.
With Kieran Marmion and John Cooney struggling with injury, McGrath would have been targeting a place on the bench against England on February 2 but instead the 25-year-old is rehabilitating the injury in the hope that he'll be fit for a European quarter-final on the last weekend in March.
Joe Schmidt is expected to include Marmion and Cooney in his squad this afternoon, while Connacht's Caolin Blade could also get the nod.
Marmion hasn't played since undergoing an operation on his ankle after starting the win over New Zealand in November, while Cooney sat out Ulster's win over Racing 92 on Saturday with a back spasm.
Joe Schmidt's mood will have been lightened by the sight of Robbie Henshaw and Seán O'Brien in full training at Leinster yesterday.
O'Brien broke his arm playing against Argentina in November, while Henshaw withdrew from that game after injuring his hamstring in the warm-up.
Both players are in contention to face Wasps on Sunday, while Devin Toner, Rob Kearney and Dan Leavy are also in the mix after missing out on the win over Toulouse last weekend.
However, Johnny Sexton has been ruled out of the final Heineken Champions Cup pool game at the Ricoh Arena as he continues to nurse a knee tendon problem. Leinster remain upbeat on his chances of making the Six Nations.
McGrath's injury complicates the selection picture for the province who yesterday registered highly rated scrum-half Paddy Patterson for their European squad at the expense of injured Munster-bound No 9 Nick McCarthy.
Jamison Gibson-Park will start against Wasps, with Meathman Hugh O'Sullivan likely to come on to the bench.
The Clontarf player has come off the bench six times for the Leinster senior team this season, while Patterson has one senior cap. Neither has played in Europe.
With Gibson-Park starting, Leo Cullen must choose between Australian lock Scott Fardy and New Zealand winger James Lowe given the restriction on the number overseas signings allowed in match-day squads.
Scrum coach John Fogarty put a positive spin on the conundrum as he described it as a "very good problem" yesterday, but Cullen will hope McGrath has a swift recovery to give him a freer hand come March.
Although it presents him with a gilt-edged opportunity, Gibson Park was disappointed for his colleague.
"Massively so," he said.
"It's not a great time of the year to be picking up such an injury but that's the way it goes. It's a cruel sport sometimes.
"He will be working hard to get back, we are looking forward to welcoming him back but at the same time it represents an opportunity for myself. I will look forward to that.
"He sits down the way in the changing room from me, so I chat to him every now and again. He's good, he's pretty down about the whole thing and the timing of it because leading into the Six Nations it would have been nice to see him play his part.
"He's a tough little bugger so he'll be going hard to get back as soon as he can. We've a couple of young talented No 9s in behind with Nick and Lukey out so they will be forward to get an opportunity.
"Hughie has figured in a good few match-day 23s already. Patsy (Patterson) has only played the one game, off the bench against the Dragons.
"Hugh is a hard-working little bugger.
"He's always in the building. He's supposed to be being home but he's always in the gym doing other stuff so yeah he's hard-working and he's picking a lot of brains seeing where he can get better.
"He's worked massively hard on his kicking since he got in and I've seen massive improvements in that.
"I've no doubt if he's called upon, he'll be ready to go."
As for the national picture, Gibson-Park has been impressed by Blade's form.
"Caolin Blade is probably one that jumps out most," he said.
"He's a good little player. I've matched up against him a good couple of times.
"He's quick and poses a threat with the ball. Good little passer.
"I suppose he's got a bit to work on with his kicking game, but I don't anyone is going to get to (Conor) Murray's level."
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