Tuesday evening's tie at Oxford's Kassam Stadium was postponed shortly before kick off after the playing surface was deemed unsafe due to a frozen pitch.
The pitch was inspected by match referee Dean Whitestone upon his arrival at the ground at 5:45pm, but unfortunately conditions worsened and the official was forced to call the game off as both sides were finishing off their warm-ups.
The last-eight tie has now been rearranged for next Tuesday (31 January 2017).
McCall said: "First and foremost, the decision is the right one.
"The pitch is unplayable, it is just frustrating that it has taken until roughly 7:30pm before the game has been called off.
"We would obviously have preferred the game to have been called off yesterday (Monday) rather than today but, in fairness to the referee, it wasn't him who looked at the pitch Monday afternoon and this morning for the two inspections.
"The surface is slippy and it is rock-hard. It is dangerous, and we can't afford anymore injuries.
"We are disappointed for ourselves and for the fans to have to come all this way for nothing, but it is definitely the right decision.
"I think both sets of players had their concerns ahead of kick off.
"When you look at the pitch following the decision to postpone, I definitely wouldn't want to send my players out there because it is dangerous.
"This is football though - we know we have to go again next Tuesday."
Following the postponement, McCall went over to the travelling City supporters over by the far side of the stadium to explain the situation.
McCall added: "I just wanted to go over and make sure they knew exactly what was happening.
"The pitch might have looked playable from the stands but it was dangerous and it was the right decision to postpone it.
"I thank them all for travelling though. A lot of them will have been at Cheltenham last Tuesday and will probably be at Oldham on Saturday as well.
"Hopefully we can put in a really strong performance for them there and bring back the three points."