The St Mary’s side host 22nd in the Championship as they round off a continuous block of league and FA Cup games since mid-November.
Stewart and Scienza missed the last two outings, having been substituted early with muscle tightness and a groin tweak respectively at West Brom.
But Eckert expects one of them to be able to play a part in the Oxford clash, as Saints look to put right a 2-1 defeat to the minnows on Boxing Day.
Speaking ahead of the match, Eckert said: “The questions are going to be for two players and they’ve both been on the pitch today.
“I’m quite positive that at least one of them is going to be available.”
Welington and Jay Robinson returned to training this week, but they were not mentioned during Eckert’s press conference. The match is likely too soon.
Eckert insists he has no concerns over the energy of his squad, who have faced Fulham, West Brom, Coventry and Norwich within the last two weeks.
“I have no doubt, because I think we’ve always been able to turn it on for games. I think it will be exactly the same for this one,” he added.