Keogh came through 65 minutes for the reserve team against Oldham on Wednesday night and impressed boss Greg Abbott.
Striker Gary Madine picked up an ankle injury against the Latics' second string but is expected to be included in the squad to face the Saints.
Striker Scott Dobie is pushing for a start against Alan Pardew's side, as is former Derby midfielder Marc Bridge-Wilkinson as the Cumbrians look to turn around their home form having lost three of their first four home games in the league at Brunton Park.
Simon Lakeland is a long-term absentee with a medial ligament injury.
Papa Waigo N'Diaye is an injury doubt for Southampton.
The Senegalese striker, who has made two substitute appearances for Saints since arriving on loan from Fiorentina, suffered an ankle knock playing for the reserves this week.
Veteran full-back Graeme Murty (knee) and young winger Kayne McLaggon (Achilles) are making progress but are not ready to be considered.
Midfielder Jake Thomson is still on international duty with the Trinidad & Tobago Under-20 squad.
Boss Alan Pardew could therefore name the same starting line-up which secured Saints' first win of the season against Yeovil last weekend.
Sporting Life