There’s been one huge change for Brendan Rodgers as he plots a route into the Champions League for Celtic.
It might look from the outside as though the Parkhead boss has the same old defensive problems as his men prepare to face Rosenborg in the second qualifying round of the competition.
Jozo Simunovic is suspended after being sent-off against Alashkert last week, Marvin Compper is injured, Dedryck Boyata is having a post-World Cup rest and Mikael Lustig has only just returned from being in Russia for Sweden.
Celtic faced the Norwegians in similar circumstances 12 months ago and handed a 19-year-old his competitive debut in the crucial centre-half role.
Since then, Kristoffer Ajer, has gone from a rookie to a regular, and Rodgers admits other teams will be watching his progress closely.
The Parkhead manager is absolutely delighted with the way his player has developed.
He said: “He’s had lots of experience now and has made big steps.
“He’s still only 20 years of age, but he’s really dominant.
“He’s a natural leader as a young guy and he’s improving all the time.
“He was thrown in against Rosenborg last time but, a year later, he’s a Norwegian international, a Treble winner and he’s developing really, really well.”
Ajer was signed by former boss Ronny Deila as a midfield player when he was only 16.
A loan spell at Kilmarnock gave him experience of playing at the back.
Modern managers are increasingly looking for defenders to build attacks from the back and Ajer is developing into the sort of stopper that’s in huge demand.
Rodgers went on: “His rampaging runs from defence are part of how we build the game from behind.
“When he attacks and steps in, he breaks lines very well.
“You get players like that. They find themselves on the edge of the box – but the problem is, they have to get back.
“I remember Gerry Taggart doing that for Leicester. He used to step forward and just barge everyone out of his way.
“Kris is very elegant, and the comfort he feels with the ball is very important. I need that with all of the players.
“We need to pass and play the way we want. But it’s really important that they can defend as well.
“Will other clubs look at him? I’ve no doubt, because he’s a young central defender who can play.
“Kris doesn’t take many risks, which is the key point.
“if you can build up play as well as defend, you can be critical for the team and how we play.”
Jack Hendry is two years older than Ajer, but he’s still bedding in at Parkhead.
Although he’s picked up two Scotland caps since arriving at the champions from Dundee in
January, Rodgers is reluctant to have him seen as the saviour of the Celtic defence.
He said: “We’ll not get too carried away. He has a lot of work to do still, but what he has is potential.
“He’s a young guy who has made great strides in a short period of time in his career.
“He has potential, but there is still a lot of work for him to do in both defensive and offensive situations.”
While defensive worries have been a consistent theme of Celtic’s European performances in recent seasons and won’t go away overnight, there are other things to think about.
Rodgers is committed to making his team a more potent attacking force and that should provide plenty of entertainment for the fans.
It looks like his decision to play a front two of Moussa Dembele and Odsonne Edouard could endure into the main league season.
Rodgers said: “It’s a long campaign. We’ll play different systems, it’ll be about what we feel a specific game needs.
“We want to attack more this season and be more aggressive.
“I’ve been really pleased in the early part of this season in terms of how that’s evolved.”