The Germans travel to Scotland with three strikers already rated extremely doubtful – Brazilian ace Raffael, Josip Drmic and Thorgan Hazzard.
But they have been further hit by an injury to key defender Christensen, who could be out for several weeks after suffering a hip injury in Saturday’s 0-0 draw with Hamburg.
Monchengladbach – who play a three-man defence – are now likely to be severely depleted for the encounter.
Highly-rated 20-year-old Danish international Christensen is in the middle of a two-year loan spell in Germany.
He was voted Gladbach’s player of the year last season, ahead of Granit Xhaka, who joined Arsenal for £35 million in the summer.
Meanwhile, Oscar Wendt, who suffered Champions League pain at Parkhead ten years ago, has warned warn his Gladbach team-mates not to get overawed by the electric atmosphere in Glasgow.
Wendt, pictured right, was a 20-year-old playing for FC Copenhagen in a Champions League clash in Parkhead in 2006. Gordon Strachan’s side won that night thanks to a penalty from current Rangers stiker Kenny Miller, although the Danes won the return.
Wendt admits he was hugely impressed with Celtic’s barnstorming start to their last game against Manchester City.
And he’s warned his colleagues what to expect.
He said: “The thing I remember most is the atmosphere in Glasgow. That was one of the best I have experienced, it’s electrifying and the players here have all been talking about it.
“The supporters at Celtic really back their players so it’s a huge boost for the home team to have 60,000 fans singing.
“So we will have to start the game well because Celtic will come at us early in the game like they did to Man City in the last match. If we can keep the crowd quiet then it will definitely help us.”
Wendt revealed he’s always followed Celtic because of the success of Parkhead icon and fellow Swede Henrik Larsson.
And he will come up against international team-mate Mikael Lustig too.
He said: “Henrik is only behind Zlatan Ibrahimovic in terms of being a legend in Sweden so I grew up watching Celtic when he was there. Everyone in Sweden followed their results and there is a lot of interest in British football.
“So I have always looked for Celtic’s results so I was pleased when we drew them because it is another chance to play in Glasgow.
“I know Mikael well from being in the Sweden squad with him and he’s a friend. He has been at Celtic for a long time now and is a very good player, so I am looking forward to seeing him.
“All Mikael has told me about Celtic is they’re enjoying working under the new manager, but when we meet we don’t really talk about football that much.
“Everyone knows about how special Celtic Park is to play at and our players are looking forward to going there.”
Gladbach come into the encounter having being held at home at the weekend by Bundesliga strugglers Hamburg, who had a man sent off after 25 minutes. Borussia also missed two penalties in a 0-0 draw.
And Wendt admitted the prize for both sides realistically is to reach third place in the Group and qualify for the Europa League.
He said: “We would have been in a better mood going to Glasgow if we’d won last weekend, especially as we should have scored three or four goals. But I think people are right when they said we could have played for another five hours and still wouldn’t have hit the net. That’s football, sometimes that happens, and by the time we arrive in Glasgow we will be full of confidence.”