The Aussie has shaken off the ankle problem which kept him out of the Dublin Tournament last weekend and is back in training.
United boss Peter Reid considered Viduka against Harrogate Town last night but opted against it, keeping him fresh for the big one on August 17.
The 27-year-old ex-Celtic frontman, United's leading scorer last term, has hinted via his agent that he is keen to quit the club, but Reid insists Viduka is very much part of his plans.
Reid said to the Yorkshire Evening Post: "The big fella trained yesterday and he trained well. Providing he's fit and there's no problems he will be playing on Sunday."
Reid has dismissed talk of a row with the player and insists that Viduka will have a big part to play for United this coming season.
Reid continued: "I had a chat with the medical people and it was decided that it was best for him to miss the trip to Ireland.
"It's been highlighted that we had a discussion on the training ground a couple of weeks ago, but that happens.
"When you look at things, any player and manager have arguments but you get on with it.
"Viduka is part of my plans and there's certainly no problems."
Reid further strengthened his strike force today by completing the 12-month loan signing of French international Lamine Sakho.
However, midfielder Colin Healy was completing his move to Sunderland.
Healy trained with Leeds yesterday but the Elland Road side have not offered a deal and the 23-year-old is now set to link up with Mick McCarthy's side.
Meanwhile, Reid dismissed suggestions that Irish international Ian Harte is on the verge of joining Portsmouth.
Pompey boss Harry Redknapp confirmed his interest in the United defender but the Fratton Park club have made no formal approach for Harte.
"I keep hearing speculation but no-one has been in touch," confirmed Reid.
Harte turned out for a reserve XI at Harrogate Town last night as Leeds ended their pre-season campaign with a 4-1 victory.