Injuries have been a constant part of Celtic's season, especially at centre-back, with that position constantly being disrupted due to Cameron Carter-Vickers' injury plagued season.
Brendan Rodgers commented on these issues in his pre-match press conference ahead of tomorrow's cinch Premiership clash with St Johnstone, saying: "It's such a shame (for Liam Scales), he's had a great run.
"That's been the biggest frustration over the course of the season, having not been able to put out our strongest XI.
"We can still finish off the season in a really high moment."
For tomorrow's match, Celtic will be without Maik Nawrocki and Liam Scales at centre-back, leaving the options available for Celtic to field in that position looking very slim.
It has been a position that has been constantly rotated this season due to issues out-with the manager's control, and he will be left scratching his head as to who to field at centre-back for tomorrow's game.
But who should start at centre-back for the champions tomorrow?
Cameron Carter-Vickers
Cameron Carter-Vickers is the Celtic defence. When he is fit, he plays, and in the situation Celtic currently find themselves in in the title race with every game being labelled with that must-win tag, you need someone like Carter-Vickers in this team.
After missing out on last weekend's Scottish Cup quarter-final clash with Livingston, The American international is available for today's game, and he will have to start against the Saints.
The only issue Brendan Rodgers may have with fielding the former Tottenham Hotspur man is the risk of causing further injury. This season, Celtic have been so reliant on Carter-Vickers that they have forced him into the squad when he isn't fully fit, further aggravating the injury and leading to him being out of action again for a prolonged period of time.
This risk has backfired on Celtic a few times this season, but with Liam Scales unavailable, it is a risk that the manager will have to take once again.
Stephen Welsh
Stephen Welsh has been in and out of this Celtic team over the last few months, with the academy product being another centre-half who has had an injury-plagued campaign.
He looked like he was going to have a big part to play this season when he signed a new contract at the start of the season, but he suffered a significant injury almost straight after signing that new deal.
However, against Livingston last weekend he was very poor, with his passing and defending all leaving much to be desired as he made up a defence that shipped two goals to the side that sit at the foot of the cinch Premiership, and could lose his place in the starting eleven tomorrow.
Gustaf Lagerbielke
The Swede could be offered a rare starting opportunity tomorrow given the current injuries the club faces at centre-back, his first since September 30th.
Previously unfavoured by Brendan Rodgers, with the manager incredibly close to shipping him out on loan in January, he could return to the team tomorrow with Stephen Welsh underperforming.
Whilst some supporters may not be convinced by him, the Swede hasn't had the luxury of playing alongside Cameron Carter-Vickers yet, and slotting in alongside the American could see a change in fortunes for the 23-year-old.