The arrival of Shane Duffy at Celtic was supposed to be the catalyst for the push towards Ten In a Row.
Instead, it proved to be just another nail in the coffin as the Hoops fell at the final hurdle.
The big Irishman arrived with Premier League pedigree and was talked about as the best defender in Scotland before he'd even kicked a ball in Glasgow.
But fast forward eight months and he isn't even making the squad.
Duffy's performances in a Celtic shirt have been alarmingly poor.
He maintained the faith of Neil Lennon, who was reluctant to give up on one of his marquee signings, but John Kennedy appears to have seen enough.
Duffy hasn't started any of Celtic's last nine matches in all competitions, failing to appear in any capacity since the 2-1 win over St Johnstone more than two months ago.
And against Aberdeen, he was left out of the squad altogether.
That's despite Celtic naming Anthony Ralston and the untested Adam Montgomery on a bench that didn't even use the full nine-man quota.
There are two main reasons for Kennedy freezing the Irishman out of the side.
One is that Duffy will have no part to play at Parkhead in the long-term or even medium-term.
While Kennedy may know his own days as manager are counting down, he wants to set the team up for the future.
He sees more benefit in giving minutes and experience to the likes of Stephen Welsh, who has shown he has the potential to be a cornerstone of next season's Celtic team.
But the fact that Diego Laxalt, Moi Elyounoussi and Jonjoe Kenny have been given minutes in recent weeks does suggest that is not the only factor behind his omission.
Kennedy is prepared to use his loan players, provided they are a clear improvement on what he has available elsewhere.
Duffy, simply, does not tick that box.
He's had chances to prove himself but looks too slow, too cumbersome, and too flakey for the intensity of the Scottish game.
And that's when the stands are empty; God only knows how he'd fare at a raucous, packed out Parkhead with 60,000 fans breathing down his neck at every touch of the ball.
He has been assessed as too much of a risk, and his chances of a prolonged future at his boyhood club have gone up in smoke.
We've seen players who have had respectable Premier League careers flounder in Scotland before, but rarely to such a dramatic extent.
Elyounoussi, for example, hasn't been a resounding hit, but has at least shown signs of what earned him his big-money move to England's top flight.
Duffy, by contrast, has looked like a severely different player. His record in aerial duels notwithstanding, he has been a flop from start to finish, and has come to symbolise the collapse of Celtic's decade-long dream.
He hasn't been the only one, of course.
He joined Vasilis Barkas and Albian Ajeti, who were each earmarked as box office signings in the summer, in sitting out altogether against the Dons.
But Duffy was seen as the safest of the lot.
And the fact that he is no longer getting a look-in is a damning indictment of a summer transfer window that could hardly have gone worse for Celtic if they'd tried.
