Fletcher will be in charge against Burnley, stepping up from his role with the club's academy after the club decided that Amorim’s time was up on Monday morning.
The former United star, who made over 340 appearances for the Red Devils and lifted five Premier League titles and the Champions League, is reportedly ready to carry out the rest of the season, as reported by journalist Ben Jacobs.
“Darren Fletcher to continue as interim manager until a suitable replacement is found.
“Backed if needed until summer, but a fluid situation with a quicker mid-season appointment not ruled out if the right candidate presents.”
Amorim oversaw 15 wins, 13 draws and 19 losses during his time in charge and the club will be patient in replacing him as they try to hire a competent manager who could lead them back to title challengers over the next few years.
Amorim, who has yet to issue a statement on his sacking, leaves United sixth in the Premier League table and will now look to find a new club before the season concludes.
The likes of Michael Carrick, Gareth Southgate, Enzo Maresca, Andoni Iraola and Oliver Glasner have been linked to the United role in the hours after his sacking as the United board look over their options.