Forest overwhelmed Morecambe in the last round, but Roy Keane's men present a massive test of the Reds' ambitions.

"It is another level up again for us, as Sunderland's result at the weekend demonstrates," Calderwood told the Nottingham Evening Post.

"We know the level of opposition we are coming up against and it will be a real test – but it is one that we look forward to.

"We have to believe that we are developing and that this is another step forwards for us.

"When we played them in pre-season, they were in the process of adding one or two players.

"They are doing OK on the shopping front, and they are creating a squad where it will be incredibly hard to get into the side, so their players' form and application will have to be absolutely spot on."

Forest are making the tie a "green day" in honour of ex-Forest manager and Sunderland striker Brian Clough, with fans of both sides asked to wear something green.

"It is green day, which I hope will fuel a few people's imagination. It would be nice to see a sea of green shirts, because that would be a fitting tribute to the man who built this club," said Calderwood.

"It would make for a great picture if we could fill the Brian Clough Stand full of people wearing green."

Calderwood insists strikers Andy Cole and Nathan Tyson will not be in his starting line-up to face Sunderlan.

He warned that it will be another few weeks before the pair are fit enough to start a game.

The pair came on against Watford on Saturday, with Tyson scoring the winner in the 3-2 victory. "It is good to have them back," said Calderwood.

"Neither of them are close to being ready to start a game. But the best development for them now will be getting bits and pieces here and there.

"We have a rest on the horizon, so we will get through the next two games and then see where we are after the international break.

"We should be able to get some training under their belts during that break, then we can look at them starting matches."

Central defender Kelvin Wilson should return from a back spasm in place of Ian Breckin.

Long-term injury absentees Paul Anderson (thigh) and Joe Garner (knee) remain out, while Lewis McGugan (torn thigh muscle) is expected to make his comeback after the international break. Arron Davies (calf) is also out.