Redknapp has been installed as the odds-on favourite to replace the sacked Sam Allardyce and by cancelling his pre-match press conference to preview Portsmouth's visit to Sunderland, the Pompey chief has only fuelled rumours of an impending departure from Fratton Park.

As someone who knows Redknapp well, Ferguson is ideally placed to judge whether he would be willing to leave his beloved family home on the south coast to take up what many now feel is the poisoned chalice of resurrecting the fortunes of the Tyneside club.

The Manchester United boss - whose team play Newcastle at Old Trafford tomorrow - feels it will be a difficult call for his old friend.

But ultimately, the disappointment of not being asked to replace Steve McClaren may just swing the verdict Newcastle's way.

"Harry is intelligent enough to know what to do," said Ferguson.

"It is a bit difficult choice for him because he has a wonderful set-up down on the south coast. He has a lovely house and his wife is settled there, so there is a decision to make.

"Certainly, there was a lot of support for him to get the England job, so it may have disappointed him when he did not get in the frame for that.

"The Newcastle job has come along straight after that disappointment so he may think he must take this one. I don't know that for certain but this is the dilemma that will face him."

Not for the first time in his 21 years at Old Trafford, Ferguson has been left non-plussed by events at Newcastle.

The Magpies have now gone through 10 managers since he came south from Aberdeen, none of whom have ended a near four-decade wait for a major trophy.

While Ferguson can understand why owner Mike Ashley would want his own man in charge, knowing former chairman Freddy Shepherd appointed Allardyce, he simply cannot fathom the logic of the process Newcastle appear to be embarking on.

"I have heard some rumours about the people Mike Ashley was talking to and it amazes me," he said.

"I don't know what you can say about the situation up there but it is a strange club."

Ferguson has already spoken to Allardyce, who was as surprised as most of the football fraternity beyond Tyneside, unable to comprehend the need for such a knee-jerk reaction just 24 games into his St James' Park reign.

The United manager was at Stoke on Sunday as Newcastle ground out an FA Cup draw and saw no sign of a club in crisis.

And the Scot - who took almost four years to win his first trophy at United - feels the Magpies misery will only continue until they learn to stand by their men.

"The expectation levels at Newcastle are too great, a lot of people are saying that now," said Ferguson.

"When you analyse the situation up there, it is beyond belief.

"They have had two managers who have won World Cups - Jack Charlton and Ossie Ardiles - as players, four who have won the European Cups as players - Kevin Keegan, Kenny Dalglish, Ruud Gullit and Graeme Souness - and Sir Bobby Robson, who took England to the World Cup semi-finals.

"You would think one of them would have won something given the right time."

Ferguson pointedly refused to discuss the influence of former England captain Alan Shearer at the club, stating: "I have my own thoughts on that - but I will keep them to myself."

But the latest managerial upheaval has not helped Ferguson's planning for tomorrow's encounter, when United will be looking for their 11th straight home win since the opening-day draw with Reading.

Ferguson admitted he had 'no idea' whether interim manager Nigel Pearson, whose team have not won at Old Trafford since 1972, was planning any changes, although he does expect former United players Nicky Butt and Alan Smith to be patrolling the visitors midfield.

Owen Hargreaves is a major doubt after suffering a rib injury in training, while Danny Simpson or, more likely, John O'Shea will replace suspended defender Wes Brown.

With Paul Scholes now due back "in two or three weeks" after returning from a long-term knee problem and Park Ji-sung earning high praise from his manager for his performance at Aston Villa last weekend just three match into a comeback from cruciate surgery, United's squad strength is starting to show through.

"Our form has been decent and after the Christmas period, I felt we were starting to look strong again in the last 20 minutes at Aston Villa," said Ferguson.

"Our record against Newcastle is outstanding but I can't carry that into the game. We have to produce the same performance level as we have done in the past and the same energy and hopefully get the job done."