The Australian striker has been troubled by an achilles tendon injury for some time and in May he was given an injection.

Keegan revealed earlier this month that he did not expect Viduka to be fit for Newcastle's opening Premier League game against Manchester United.

He has now confirmed the news, although he remains hopeful that Viduka will not miss too much action.

Keegan will have an otherwise fully fit squad to choose from for the clash against United, with Michael Owen, Joey Barton, and Obafemi Martins all set to be in contention.

Martins has rejoined the Magpies squad for the Mallorca Summer Cup following the death of his mother, Owen is recovering from slight calf trouble and Barton is returning to fitness after being released from prison.

Keegan told the Evening Chronicle: "Mark will definitely not be ready to start the season, but he should be back in training in the next week.

"With the catching up he has to do, I would say, if everything goes to plan, Mark will miss the first two or three games just because of match fitness.

"Other than that, I don't think there is anybody who I could say, at the moment, will miss the start of the season."