The Danish playmaker has missed our last two matches because of a back injury.
Outstanding in his last appearance against FC Dnipro on February 27 - when his free-kick sparked our comeback from 2-0 in the R32 tie as we went on to win 3-2 - Christian was then ruled out of our next match against Cardiff, Denmark's friendly against England at Wembley and Saturday's derby at Chelsea.
But he has returned to training this week and played a full part in Tuesday's session.
Head Coach Tim said: "Christian has contributed well in his last few matches, both goals and assists and it's great to have him back in contention."
We'll have full team news ahead of the first leg tomorrow afternoon...