If you could have asked any United fan in early June which players would be first on Jose Mourinho's team sheet David de Gea would be one and Anthony Martial another.
At a time before key signings had been made, most would then have probably plumped for Chris Smalling next ahead of individuals like Wayne Rooney, despite his role as club captain.
The former Fulham centre-back has developed into a real defensive leader over the last two seasons and was often wearing the armband himself by the end of Louis van Gaal's tenure.
But, three months on, the debate is now whether Smalling even gets on the pitch at all.
Following a late return to pre-season training as a result of Euro 2016, Smalling then picked up an injury that ruled him out of contention to make an impression on Mourinho.
He was also suspended for the first game of the Premier League season which led the new boss to make plans that didn't include him.
What we perhaps had not envisaged was just how well Eric Bailly and Daley Blind would play together as United's new first choice centre-back pairing.
Who would have been an automatic name on the team sheet in early June?
Bailly wasn't at the club, and even when he did arrive there were reservations about whether he was ready to be thrown straight in, while Blind was predicted to be an early Mourinho casualty.
Even if he were to stay, most felt the Dutchman would be a squad player at best.
But in Smalling's misfortune, the other two have actually significantly prospered.
Bailly looks every bit a top class Premier League defender.
He's quick, strong, powerful, composed both with the ball and without it, commanding in the air, able to read the game and identify danger, all with a distinct class rather than the rash and raw talent he was initially billed as.
Alongside the Ivorian, Blind has continued to defy the doubters.
His physical profile doesn't typically match Mourinho's preferred defender, but he's one of the most intelligent players there is and that makes him invaluable.
People thought LVG was mad for persisting with Blind as a centre-back and the player was still described as 'makeshift' and 'stop gap' even at the very end of last season and into summer despite playing virtually every game in all competitions at the heart of a defence that conceded the joint fewest goals in the League.
Now that it's Mourinho playing Blind in the middle it is deemed as a master-stroke - investigating why the exact same decision made by two different managers has been perceived so differently is debate best left for another day.
Smalling is the unfortunate loser at the moment.
Time waits for no man in modern football and he'll have to be patient for his chance to come back around, although it's hard to see when that will be with things going so well in front of him.