That is according to Netherlands legend and Cameroon manager Clarence Seedorf.
Jose Mourinho took over from Louis van Gaal at Manchester United in the summer of 2016.
Despite winning three pieces of silverware in his first campaign, the former Chelsea boss has failed to mount a Premier League title challenge with the Red Devils.
That once again looks unlikely this season, with United eighth in the table after 12 matches having already notched up four defeats.
Seedorf admits it was always going to take time after the retirement of Sir Alex Ferguson in 2013 for success to return to Old Trafford.
And he claims losing a number of legendary players also made the job harder.
But despite that, Seedorf says there needs to be a decision made whether Mourinho is the right profile of manager to turn things around.
“After Ferguson it’s just difficult,” Seedorf told Sky Sports.
“It’s a transition phase still, and not only Ferguson but the players that he had.
“Once the last team of [Paul] Scholes, [Ryan] Giggs and [Wayne] Rooney fall away, it’s a part of the club that leaves the heart of the team. To replace that you need to have patience.
“That’s not only happened with Manchester United, it’s happening in Milan but they need to keep on working.
“I think they have all the means to be able to stay competitive.
“He [Mourinho] definitely has an interesting track record.
“It’s up to the club and him to understand whether his management still has influence and he can turn things around.
“He definitely has the capacity – I don’t think we have to discuss Mourinho’s qualities but sometimes things just don’t go and that could be the main decision to stop working with each other.”