Speaking on Monday Night Football about United's poor start to the season and performances under Amorim, Carragher delivered a scathing assessment.
He said: " I think Amorim is still in charge because the people in power at United have made so many mistakes both on and off the pitch that they almost don't want to admit that they have made another mistake.
This is a disaster for United and Ruben Amorim. What he did at Sporting Lisbon was fantastic and Amorim looked like a rising star in coaching.
But appointing a coach with a three-man defence has never been in keeping with United's tradition. I think the sooner the decision on the manager is made, the better for everyone.
We are waiting for the inevitable. Unfortunately, no one wants to see people lose their jobs, but this has to end as soon as possible."
Jaime Carragher added that the Red Devils' board need to take some responsibility because they know Amorim will apply a similar system to what he did at Sporting Lisbon.
"Amorim's darling is the 3-4-2-1 system, which is like asking Jurgen Klopp's team not to press, or Pep's Man City not to pass short balls in midfield.
Omar Berrada, Jason Wilcox and Sir Jim Ratcliffe brought Amorim in. I think every other Premier League manager would look at United and think 'I can do better than that'.
The only positive for United is that they did not go all-in on Amorim's system. Ineos spent big but did not buy midfielders or full-backs.
The players they bought could easily be converted into a back four, with Bruno Fernandes playing as a No. 10, Mbeumo on the right and Matheus Cunha able to operate on the left.
MU has made many changes but the coaches are still given more time. Amorim has not been there for a full year but things cannot get any worse."