Lions head coach Warren Gatland and his Leinster counterpart Joe Schmidt are on a collision course over Sean O'Brien's knee that could threaten his participation in the three-Test series against Australia next month.
While Leinster expect O'Brien to be in contention for this Saturday's Pro12 final against Ulster, Gatland revealed that he had already ruled the Tullow flanker out of Saturday's game – and also the first two Lions tour matches next month.
That means he may only have a week to prove his readiness for the June 22 opening Test in Brisbane if, as the Lions insist, this latest injury takes two weeks to heal.
O'Brien has already suffered from calf problems in recent months and he underwent complicated hip surgery last summer, a procedure that ruled him out of action for the first half of the season.
O'Brien, who will spend today with a foot in both camps as he divides his time between the Lions in Carton House Maynooth and Leinster in UCD, injured his knee in Friday's Amlin Challenge Cup final win over Stade Francais.
Having been forced off prematurely, he told reporters afterwards that he did not expect to suffer any long-term effects from the bone-on-bone collision and Schmidt was similarly upbeat.
And Leinster maintained that stance yesterday, confirming that O'Brien needs to prove his fitness on Thursday to have any chance of playing on Saturday, but they insisted that he remained in contention to start.
However, Gatland's view was entirely contradictory and he revealed that O'Brien had already been assessed by his own medical staff, one of whom is the Irish team doctor.
"He has come in and been looked at by the medics," said Gatland. "Hopefully he's going to spend this week with us. It's a bit of bone bruising by all accounts.
"That's only a couple of weeks maybe. We are just hoping it's not longer than that.
"With bone bruising it's a little bit unpredictable. But he's come in and they have said it was a little bit more positive than they had first thought, which was good."
To add further confusion on a day of entirely mixed messages, the Lions issued a brief statement late last night which hardly clarified the issue.
"Sean O'Brien was this evening checked by the Lions medical staff in consultation with their Leinster counterparts," said the statement.
Lions head doctor James Robson said: "Given the proximity to the tour we are grateful to Leinster for being able to assess Sean. He is in better condition than we thought and he continues his recovery at pace."
If O'Brien is ruled out of action this week, Leinster will be peeved that he has blown their cover as they would have preferred to let Ulster believe that their back-row enforcer was available.
However, should Leinster persist in running O'Brien though a rigorous fitness test in Thursday's training session, the Lions coach will not be best pleased given his declaration yesterday, even if the late statement seemed to row back on the earlier expressed concern.
The official line from assistant Greg Feek was: "We're just going to wait and see on Sean O'Brien, give him as long as we can.
"He got a bruise on his knee. We will see how that settles down. It is a new injury. Hopefully, he'll be alright. He won't train today."
Brian O'Driscoll, whose back spasm kept him out of the RDS final win last Friday is, however, expected to play, even if Gatland also had communication issues with Leinster.
Mercifully, that was only because Schmidt had mistakenly supplied his fellow Kiwi with an incomplete telephone number.
"Obviously Brian O'Driscoll is hoping to be fit to play this week," Gatland added.
"He is on his feet again and hoping to play this weekend. We've been quite lucky at the moment. Fingers crossed for the two finals this week (England host their league final between Northampton and Leicester) so the guys can turn up on Sunday and fly out on Monday."
For Leinster, Fergus McFadden's neck injury remains a real concern ahead of the Pro12 final, but the shoulder injury sustained by Richardt Strauss is not a serious issue.