McGeechan careful not to write off a Lions starting role for sexton
The only certainty on a Lions tour is uncertainty.
Injuries - Jamie Heaslip expects at least 10 - and form can dismantle every single line of the First XV so tentatively committed to paper just a few short weeks before.
Ian McGeechan - indubitably the Lion King, with a quarter century of experiences as player and coach behind him - warns us that presumption is the midwife of terrible twins, hubris and failure.
"You can't start the tour with a Test team," says the venerable 'Geech', twice a player in red before embarking upon five tours of duty as a coach.
"I'll be the first to put my hand up and say: what I thought was going to be the Test team at the start of a tour, as coach, was never the Test team. Ever.
"You've got to have this open mind. As a coach, you've to be open-minded about what you're seeing, the combinations you've put together.
"I go back to Brian O'Driscoll and Jamie Roberts in 2009. The best centre partnership in the world, easily.
"Never played together, but they just had this rapport. You'd see them in an airport lounge, or in a hotel lobby with a laptop or just talking. So on the field, they'd suddenly got this understanding of how to bring the best out of each other."
The Scot cannot be absolved of the curse of presumption in his role as a pundit now, either; last month, he insisted that Owen Farrell must start at out-half ahead of Jonathan Sexton.
Now, he is not so sure.
"Sexton hasn't been on top form for the last month of the season, Farrell has been playing the same intense games," he says.
"To me, the two most competitive animals in the backs are Sexton and Farrell. These fellas are targeted every time they play and you look at how they come back, the way they challenge players within the team.
"Just listen to players talking about the two of them. There is huge respect and that's what the Lions needs. That Farrell/Sexton axis I think is still very much in play for the Test match."
Heaslip reckons Leinster's famous five could all start the First Test; then again, history tells us fate may dictate that the reverse could also be true.