Kristoffer Ajer could be a doubt for Celtic's opening Europa League clash with Rennes after revealing he will be missing for at least two weeks.

The Norwegian defender has been forced to pull out of his country's Euro 2020 double-header against Malta and Sweden after picking up a groin injury in Celtic's thumping 4-1 win at AIK Stockholm in the Europa League last week.

Hoops boss Neil Lennon had insisted Ajer had a chance of playing in the Old Firm encounter, but he didn't make the squad.

Celtic sign Lee O'Connor from Manchester United

And the injury is set to keep Ajer out for a couple of weeks. He said: "I've been told I have to rest for two weeks."

That means he will miss Celtic's next league game at Hamilton Accies and would be touch and go for their opening Europa League match in France against Rennes.

Norway boss Lars Lagerback admitted the loss of the 21-year-old was a big setback for them.

He said: "Losing Kristoffer is not ideal.

"We have now had to bring in another defender and will have to change what has been a settled and successful defence.

"At international level, continuity is very important and everyone knows Kristoffer has matured into a top player for club and country."