Rusk will take temporary charge of the team following the sacking of Russell Martin on Sunday, after a 5-0 defeat at home to Tottenham Hotspur, which leaves the club nine points from safety in the Premier League.
Martin picked a strong team for the win over Stoke City in the last round, and even though they are now in much deeper relegation trouble than they were a month ago, they may be reluctant to put all their eggs in the Premier League basket, with a semi-final place at stake.
One player who probably will not feature is Kamaldeen Sulemana, who was handed his first Premier League start of the season on Sunday, but was hooked by Martin inside 15 minutes with the Saints 3-0 down, sparking an unhappy reaction from the Ghanaian winger.
Six-foot-seven striker Paul Onuachu was proving hard to deal with when Liverpool edged a five-goal thriller between the sides here last month, before going off injured, but he returned from that setback on the bench at the weekend, and is in contention to feature.
Fellow striker Ross Stewart is out until the new year though, along with full-back Juan Larios, with Rusk also without midfield duo Adam Lallana and Will Smallbone either, as both are recovering from hamstring issues.
One player who was fit to return to the starting XI was Jan Bednarek, and that was well timed with Jack Stephens still serving a suspension, even if the Polish international did concede five first-half goals at the weekend.
Aaron Ramsdale is expected to return to the fold this week, bringing some continuity to a position that has seen Joe Lumley and Alex McCarthy swap around over the past few weeks, to little effect.
Southampton possible starting lineup:
Ramsdale; Sugawara, Walker-Peters, Harwood-Bellis, Bednarek, Manning; Aribo, Ugochukwu, Mateus Fernandes; Dibling, Onuachu, Armstrong
Written by
Andrew Delaney