Saints boss Alan Pardew's search for a striker came to a successful conclusion on Monday when he snapped up Lambert for around £1million from Bristol Rovers, and the 27-year-old is in line for an immediate debut.
Winger Lee Holmes is fit after an ankle injury and could come into contention having been an unused substitute during Saturday's 1-1 draw with Millwall.
Anthony Pulis, Olly Lancashire and Simon Gillett will also push for starts if Pardew opts to make changes.
Young striker Kayne McLaggon remains Saints' only long-term absentee, and is likely to be sidelined until November as he continues to recover from a ruptured Achilles.
