The Northern Ireland star limped off injured early in the second-half of his side’s 1-0 home World Cup qualifying play-off defeat by Switzerland in Belfast last night.
With Christiansen needing a win to relieve the pressure after a run of four straight defeats, he will be hoping Dallas’ injury isn’t too serious.
Dallas, 26, was in full flight running down the wing when he was scythed down by Swiss defender Fabian Schar – a challenge Irish boss Michael O’Neill said deserved a red card.
He said: “The tackle by Schar was a borderline red card, the referee certainly didn’t do us any favours tonight.”
O’Neill was also upset by the decision to award Switzerland a match-deciding penalty in the first leg game “bewildering”.
Romanian referee Ovidiu Hategan inexplicably pointed to the spot in the second half when Xherdan Shaqiri’s shot hit the top of Corry Evans’ arm when the Northern Ireland midfielder had his back turned.
Ricardo Rodriguez converted from the spot to give the Swiss a 1-0 lead going back to Basel on Sunday and Evans was booked to rub salt into the wound, meaning he will miss the second leg.
“It’s staggering really that the referee can give that penalty decision in that situation,” O’Neill said. “He was six yards from the incident, he has no one in his line of sight.
“Corry has just gone to block it, his body is turned and the ball actually hits him more on the shoulder than the arm so it is incredible.
“I thought he had blown for a foul or for offside, so to give a penalty for that, when nobody appealed, it is bewildering really.”
O’Neill wants his side to channel their sense of injustice and turn the tie around on Sunday.
“We are still in the tie, we are only 1-0 down and maybe we will get the good fortune of having a referee who will give us a decision like that in the second leg.”
England have suffered another injury blow on the eve of their friendly with Germany after goalkeeper Jack Butland broke a finger in training.