The Tannadice club are understood to be keen to make a swift appointment following the abrupt departure of McNamara on Saturday evening.
His time in charge at Tannadice came to an end in the wake of Saturday’s 2-1 Premiership loss away to St Johnstone.
The defeat, in a game in which United had led 1-0 and the Saints were reduced to ten men, left the Tangerines still sitting second bottom of the table, with just one solitary league win to their credit all season.
Tannadice chairman Stephen Thompson spent yesterday in meetings with McNamara to thrash out a severance package for the now-departed boss.
He will now turn his full attention to appointing McNamara’s successor this week to ensure United have a new man in the dugout for this weekend’s crunch trip to Firhill to face bottom club Partick Thistle.
Thompson has wasted no time in drawing up a shortlist and among McNamara’s possible successors are his former Celtic team-mate Malky Mackay, who was sacked by Wigan Athletic in April after less than five months in the job.
Former United player and current Ross County manager Jim McIntyre is believed to have attracted attention through his impressive start to the new campaign, along with Mixu Paatelainen, who had a spell as a player at Tannadice during the late 1980s and early 1990s.
Northern Ireland boss Michael O’Neill also has his admirers within the United boardroom but being on the verge of leading his country to the European Championship finals in France next summer would make it hard for him to be lured away.
McNamara’s dismissal came as no real surprise following a run of disastrous results, which prompted the Tannadice board to take cohesive action.
The 41-year-old assumed control of the team from Peter Houston in January 2013 and reached the Scottish Cup final in 2014 as well as the League Cup final back in March. In the Scottish Cup showpiece they lost to 2-0 to St Johnstone at Celtic Park, and in the League Cup final they were beten 2-0 by Celtic at Hampden Park.
The former Celtic, Aberdeen, Wolves and Scotland player, though, found fans turning on him when it became public that he earned a commission from the sales of Ryan Gauld to Sporting Lisbon and Andy Robertson to Hull City as a result of a clause in his contract.
From that point on, his position looked untenable and worsening results on the field saw his credibility drop.
McNamara wasn’t helped by the joint sale of Stuart Armstrong and Gary Mackay-Steven to Celtic back in the January transfer window, before losing influential striker Nadir Ciftci to the Parkhead club during the summer. Add in Gauld and Robertson and McNamara had lost arguably the five best players in his team. United’s only league win so far this season was away to lowly Motherwell in early August, and the manner in which they threw away victory in Perth at the weekend proved the final straw for those who run the Tayside club. In total, he was in charge of United for 99 league matches, winning 38, drawing 22 and losing 39.