The 32-year-old Australian has missed the club's last four games with a calf injury, and his physical presence has been sadly lacking, no more so than at the weekend when the Magpies looked toothless in their efforts to recover from an horrific start.

Pompey's 4-1 win at St James' Park left manager Sam Allardyce facing a major task to restore confidence ahead of a hugely important derby trip, and Shearer, whose career was ended by a knee injury in a 4-1 win at the Stadium of Light two seasons ago, knows just how vital Viduka's participation could be to £17million hitman Michael Owen.

He told PA Sport: "Mark is a big player and, on his day, he is as good as anyone at holding the ball up.

"You have seen over the years what he brings to his teams. Yes, he does have a few injuries, but he has had that all his career.

"I hope he is fit for Saturday because Newcastle are probably a better side with him in it at the moment than without him.

"Fingers crossed, he will be fit for the weekend."

Shearer's comments came as he promoted his 'Ultimate Football' DVD, having been at St James' on Saturday to witness a hugely uncomfortable afternoon for Allardyce and his players.

He is hopeful that debacle, which saw the Magpies concede a three-goal lead with only 11 minutes gone, was a blip which can be quickly addressed.

Shearer said: "It was disappointing, it was poor. The game was lost after 12 or 13 minutes, which was disappointing.

"It was just a bad day at the office all round, a really poor team performance. But they do not need anyone to tell them that.

"I was very impressed with Portsmouth - I have been all season - the way they passed it around and played football. They certainly looked a better team than we did on Saturday.

"But hopefully that was just a blip and a one-off and the big one is on Saturday now."