Eric Garcia and Phil Foden complete a trio of Academy graduates in the starting XI with another couple on the bench in Adrian Bernabe and Ian Poveda-Ocampo.
Only Gabriel Jesus and Bernardo Silva keep their place this evening.
Bravo, Walker, E Garcia, Otamendi, Angelino, Doyle, Foden, Bernardo, Mahrez, Aguero (c), Jesus
Subs: Carson, Stones, De Bruyne, D Silva, Cancelo, Bernabe, Poveda-Ocampo
McCarthy, Valery, Stephens, Bednarek, Danso, Romeu, Hojbjerg (c), Ward-Prowse, Armstong, Boufal, Long.
Subs: Gunn, Vokins, Yoshida, Vestergaard, Redmond, Adams, Ings
City's line-up suggests a familiar 4-3-3, though it might be just after kick-off before we figure out who is playing where this evening.
With Ilkay Gundogan rested, Fernandinho suspended and Rodri injured, it will be interesting to see who gets the holding midfield role.
It could be debutante Tommy Doyle - with Bernardo and Foden further forward.
Up front, Jesus and Mahrez will flank skipper Sergio Aguero while Garcia and Nicolas Otamendi are tonight's central defensive pairing.
Blues looking for early silverware
City know that victory this evening will mean a quarter-final berth and that we will be just three games away from a third successive final.
With plenty of big guns left in the Carabao Cup, it is likely to be harder than ever to win the competition this season.
Prior to this evening’s matches, Liverpool, Chelsea, Manchester United and Arsenal were all still in with a shout – though at least two of those teams will be eliminated as they play each other in Round 4.
Aston Villa take on Wolves and Everton face Watford, meaning five Premier League sides (with the winners of City v Southampton) will progress to the last eight at least, with Leicester City looking to make it six when they take on League One Burton Albion.
There is, however, a guaranteed representative from League One and League Two, with Oxford playing Sunderland and Crawley meeting Colchester.
The draw takes place on Thursday morning – details here, should we proceed.
The last round...
Stats and facts
City have never beaten Southampton in the League Cup, with the Saints eventually progressing in 1978, 1982 and 1999.
Southampton have lost eight and drawn one of their last nine visits to the Etihad.
The Blues are unbeaten in 13 League Cup games since 2016, winning nine and drawing four – all of which ended in penalty shoot-out victories.
Southampton have decent form in the League Cup, having won eight and drawn two of their last dozen ties – impressively, none of those games resulted in a clean sheet.
If City score four goals this evening, it will mean the Blues have scored 50 in all competitions this campaign in just 16 games – we currently have 46 goals from 15 games at an average better than three per game.