NorthEast, who were the early pacesetters, have slipped to the fifth position due to a recent spate of unfavourable results while Mumbai are second and have the same number of points as league leaders ATK but have inferior goal difference.
ATK are top with 12 points from seven matches, followed by Mumbai, who also have 12 points but have played a match more.
Third placed Delhi Dynamos have 10 points from seven games, as have fourth Chennaiyin FC and fifth NorthEast, their places being determined by their goal differences.
A win for Mumbai will catapult them to the top with 15 points while a victory for NorthEast will also help them reach the first spot with 13 points.
NorthEast -- who are playing after a gap of almost a week -- lost to ATK in their last game despite leading at one point of the match while Mumbai played out a 1-1 draw against Chennaiyin FC.
NorthEast coach Nelo Vingada is not known to tinker a lot with his playing eleven but goalkeeper Subrata Paul's injury in the last game could be critical for the hosts.
The in-form veteran picked up a knock in the second half and with second choice custodian T.P. Rehenesh already nursing an injury, the home side might have to start with a foreign keeper in Wellington Gomes.
Emiliano Alfaro -- the highest scorer so far with five goals --will again be tasked to find the back of the net and the Mumbai defence will have to be on their toes to negate his threat.
Visiting centre-back Lucian Goan -- who has so far made 32 tackles in the tournament -- will be facing his toughest test yet with Nicolas Valez and Yusa Katsumi forming a strong attacking force for the home team.
The Mumbai attack is not bad either and the fact that star marquee Diego Forlan has found the net twice in five games is good news.
Britto Alves has been impressive too and so has been Haitian Sony Norde.
In the last match, Forlan played behind Norde in their offensive line-up and it remains to be seen whether coach Alexandre Guimaraes deploys the same strategy against NorthEast at the Indira Gandhi International Stadium as well.
In the past, NorthEast have won two matches against Mumbai in the four they have played. Mumbai won once while the other match ended in a stalemate.