Viduka has had an injury-plagued first season at Newcastle

Newcastle striker Mark Viduka could be out of action for between three and six months because of an Achilles problem, manager Kevin Keegan has revealed.

Viduka, who has scored seven goals this season, had been due to have an injection for his long-standing Achilles injury on Thursday.

"If it's three months then he won't miss much of next season," boss Kevin Keegan told BBC Radio Newcastle.

"We'll know more about that in 10 days time when he visits the specialist."

The Australian international joined Newcastle on a free transfer from Middlesbrough in June 2007.

The 32-year-old signed a two-year contract, with the option of a third year, after rejecting a new Boro deal.