Adam El-Abd and Chris Wood will be missing for the league leaders.
Defender El-Abd limped off with a hamstring injury during Tuesday night's 1-0 win over Notts County and although the problem is not too serious he will not be ready for the weekend.
Tommy Elphick, who returned from a bout of mumps to replace El-Abd in midweek, should start at centre-half.
Striker Wood is on international duty with New Zealand and with Ashley Barnes still a doubt after missing out on Tuesday with an ankle knock, Glenn Murray could start on his own up front.
Alan Navarro will be on the bench again after playing 90 minutes for the reserves in midweek following a cruciate injury but fellow midfielder Jamie Smith (foot) and defender Jim McNulty (ankle) are still out.
Influential centre-back Scott Cuthbert will be available for Swindon's tough away trip.
Cuthbert sustained a fractured cheekbone in the draw against Dagenham & Redbridge two weeks ago and, despite playing in last Saturday's stalemate at Huddersfield, had appeared set for minor surgery.
But scan results on Thursday have shown that is not necessary and he will continue at the heart of Town's defence at the Withdean.
Loan signing Alassane N'Diaye is close to match fitness but again looks set to miss out against the Seagulls, while striker Vincent Pericard and defender Milan Misun (both knee) continue to be sidelined.
Elliot Benyon, Simon Ferry, Jon-Paul McGovern and Alan O'Brien all gained valuable minutes for the club's reserves on Monday and are pushing to be involved.
Goalkeeper David Lucas should continue having suffered no adverse effects on his return from an arm infection last weekend.