Southampton will check on defenders Frazer Richardson and Dan Harding.
Richardson should return after missing last weekend's 3-2 win over Nottingham Forest with a calf strain.
Jack Cork filled in at right-back in Richardson's absence and will revert to his preferred midfield role, meaning Morgan Schneiderlin drops to the bench.
Harding was also sidelined last week after jarring his knee in training, and if passed fit he will challenge recent signing Danny Fox for the left-back spot.
Midfielders Richard Chaplow (tendinitis) and Steve de Ridder (foot) returned as substitutes against Forest and should be involved again.
Centre-half Dan Seaborne is out of hospital but still recovering from injuries sustained in an assault outside a nightclub.
Birmingham boss Chris Hughton must decide whether Nikola Zigic is ready to play any part.
The striker, who is yet to feature this season, has returned to full training following his groin injury but has no match practice under his belt, meaning manager Hughton must decide whether to name him in his matchday 16 or first get the Serbian involved in a behind-closed-doors friendly.
Midfielder Morgaro Gomis will be assessed ahead of the trip to St Mary's having missed Thursday's 3-1 defeat to SC Braga with a groin injury sustained in last Sunday's 3-0 victory over Millwall.
Including Gomis' absence, Hughton made a total of six changes against the Portuguese side from the XI who saw off the Lions and the likes of Steven Caldwell, Chris Burke, Jean Beausejour, Curtis Davies and Chris Wood - all rested to the bench - will look to come back in.
Wood's hat-trick against Millwall means he is almost certain to start in attack against Saints, with the other strike role to be competed between Adam Rooney and Marlon King, who found the net on his full debut against Braga.
Keith Fahey (groin) remains a couple of weeks away while fellow midfielder Jordon Mutch (ankle) is a long-term absentee.