By Craig Hope

NEWCASTLE United striker Mark Viduka could be sidelined for up to six months in a bid to get over a niggling Achilles injury.

The Aussie ace had been expected to receive an injection this week and be back in time for the start of pre-season training in early July.

But Toon boss Kevin Keegan confirmed on Thursday that he will be without the 32-year-old for between three and six months.

"Mark Viduka could be out for three to six months," KK told Newcastle World TV.

"We will know more in two weeks, and will inform you then. If it's three months, it won't be a major blow.

"Mark has been very good for us and when he has started games we have generally played well and got a result.

"But if he's out for six months then it is a major blow."

Viduka has netted seven goals from 21 starts in his first season on Tyneside.