With the Saints searching for their first win in six games, they will be hoping Alex Neil's men do not thrive off their underdog tag, as anything other than a win will only further thicken the gloomy air surrounding the club.
The winner of the replay will host Arsenal in the fourth round.
Late drama last time out
Being a division above their opponents, Southampton travelled up to East Anglia knowing that they were naturally heavy favourites to progress when the sides met ten days ago.
However, current form suggested there could be an upset on the cards. Claud Puel's side had lost all three Premier League games over Christmas, while Norwich began 2017 with a definitive 3-0 victory of Leeds.
As it was, the encounter turned out to be an intriguing one, if far from a classic. Captain and star defender Virgil Van Dijk put the visitors ahead in the first half, with a volleyed finish that most strikers would have been proud of.
After the break, a mistake from Southampton's young goalkeeper Harry Lewis forced him to give away a penalty, which was converted by Steven Whittaker. Nevertheless, the Saints restored their lead midway through the second half, with another centre-back, this time Maya Yoshida, getting on the score-sheet with a powerful header.
With the final whistle looming Puel's men, perhaps thinking they had got the tricky job done, shot themselves in the foot, allowing Norwich striker Steven Naismith the simplest of headers. The Scotsman made no mistake, drawing the Canaries level. This turned out to be the last notable act of the game, meaning the sides would have to do it all again in just over a week's time.
Pressure all on the Saints
The expectation of winning and winning comfortably can be difficult to handle at the best at times but for Southampton, it is especially challenging due to their recent performances and results. Southampton have lost each of their last four games, and manager Puel has been heavily criticised for his negative tactics, endless squad rotation and lack of activity in the transfer window so far.
The Saints so desperately need to regain that winning feeling to lift spirits on the South Coast, but they will have to cope with going into this replay knowing that they will officially be in a crisis if they are not victorious.
Norwich in contrast, come into the game with absolutely nothing to lose. Although their recent form is also less than impressive and Alex Neil is fighting to keep his job, winning promotion back to the Premier League is their priority this season; any success in cup competition is simply a welcome bonus.
Southampton's newest injury concern is midfielder Steven Davis who is unavailable after picking up an injury in the defeat against Burnley. Defenders Virgil Van Dijk and Ryan Bertrand are also doubtful.
Sofiane Boufal, Charlie Austin, Jeremy Pied, Matt Targett and Alex McCarthy are all side-lined for the foreseeable future.
As for the visitors, they will be without midfielder Jonny Howson, who is nursing a calf injury. Louis Thompson, Conor McGrandles and Carlton Morris will also not feature.
After seeing red against Rotherham last Saturday, striker Nelson Oliveira is suspended.
There's history between them
Southampton's Fraser Forster and Nathan Redmond both played for Norwich, with the latter being acquired by the Saints directly from their opponents on Wednesday last summer.
The last encounter between Southampton and Norwich at St Mary's went the hosts' way, as they eased to a 3-0 victory in August 2015.
The two sides met five times in the FA Cup, Southampton have won twice, Norwich have won once, and the upcoming match will be the second ever replay.