A big game for both clubs, to kick off a big week for Saints who really need to keep winning if they are to mount a genuine push for the play offs, but there is good news pre match and Saints should have a strong squad out.
There appears to be no no move either way on the injury front, all those long term are still out and no one added to that list, however Flynn Downes should return to the squad after his one match suspension and Oriol Romeu also took a step forward in his fitness plan by getting 45 minutes in for the U21 side in midweek.
At Millwall we showed we had the spirit, that we weren't a one man side, in the manner that we fought our way back into the game, but we missed Leo Scienza who should return on Saturday and it was a little disappointing that we wouldn't see out the game in the final stages.
So this will raise a few questions about who will be in and out of the side for the visit of Birmingham.
In goal I can't see much of a change and contrary to some viewpoints, I don't think Gavin Bazunu could be blamed for any of the goals, indeed he made several decent stops at crucial times.
In defence we looked shaky at the New Den, I can see why Jack Stephens came back into the side at the expense of Joshua Quarshie, but to be honest it didn't work, so it will be interesting to see what Tonda Eckert does in this department.
In the centre of the park I would hope that Flynn Downes will return to bring experience back into the mix, at Millwall, we had two many youngsters with no experience, Casper Jander is still only 22 and he was partnered by 20 year old Cameron Bragg, add Jay Robinson into the mix and 21 year old Joshua Quarshie and we had too many young players with little experience in the side.
So I would hope that Eckert will make 3 changes, in the back 3 I would hope that Jack Stephens drops out and replaced by either Quarshie or Ronnie Edwards.
In the centre of midfield we need the experience of Flynn Downes and in the attacking third Leo Scienza in for Robinson.
That will give us the balance of youth and experience we need.
Again it is our bench that can change games, at Millwall after a lacklustre first half we perked up in the second after key substitutions, although I think Joe Aribo did himself no favours when he came on.
But with the likes of Oriol Romeu, Ryan Fraser, Jay Robinson, Kuryu Matsuki & Ronnie Edwards all chomping at the bit, as we go into a tough winter programm it will not just be the quality in the squad but the quantity will count.
Saints win this game and they pull themselves in sight of the play offs and only a point behind Birmingham themselves who are pushing for the play offs, lose this and we will be 7 points behind not only them, but the top 6.
Win it though and we make another statement of intent and we will be right behind the play off spots and chasing pack.
Tonda Eckert has to make sure that the late disappointment at Millwall was a one off and that we can return to the form we displayed in the games preceding that fixture.