The former Real Madrid manager is the favourite to succeed the Dutchman if the 20-time English champions run out of patience with Van Gaal.
Mourinho will need to tear it up and start again because there is no evidence of a team there any more
The 64-year-old is coming under increasing pressure following successive defeats by Sunderland and FC Midtjylland ahead of their trip to League One’s Shrewsbury Town in the FA Cup on Monday night.
Former Tottenham Hotspur manager Redknapp believes Mourinho will need to completely overhaul the United squad after United have fallen further behind their title rivals.
“It seems to be a case of simply delaying the inevitable for Van Gaal,” Redknapp told The Telegraph.
“Mourinho will have a massive task on his hands if, as expected, he does succeed the Dutchman as manager. They have spent over £300 million under David Moyes and Van Gaal but are nowhere near where they want to be.
“They are way off it, no more than a fourth or fifth-placed team in the Premier League. Whether it was the manager, or head of recruitment, who signed all these players, somebody has to put their head above the parapet and admit to it. If you worked in a company and spent millions making bad decisions you’d get the sack, so why should it be any different for football?
“Mourinho will need to tear it up and start again because there is no evidence of a team there any more. They are miles away from Manchester City, who have five or six fantastic players, and will probably add another three or four more when Pep Guardiola comes in over the summer.”
Mourinho was sacked by Chelsea in December after their ninth defeat of the season at Leicester City.
The Portuguese coach has won three Premier League titles during two stints at Stamford Bridge.
United face Shrewsbury in the FA Cup fifth round on Monday night before Arsenal make the trip to Old Trafford next Sunday.
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