Adam Lallana and Davy Propper have been building their fitness following injury issues and could be in contention to replace Bissouma but fellow midfielder Dale Stephens was this week allowed to join Premier League rivals Burnley.
Ole Gunnar Solskjaer has no fresh injury worries ahead of the first of two trips south in the coming days.
Centre-back Axel Tuanzebe is nearing a return to first-team training but will not be available before the international break.
Brighton provisional squad: Ryan, Steele, Lamptey, White, Webster, Dunk, Bernardo, Burn, Veltman, Alzate, March, Gross, Lallana, Propper, Mac Allister, Molumby, Jahanbakhsh, Trossard, Connolly, Maupay, Gyokeres.
Man Utd provisional squad: De Gea, Henderson, Grant, Dalot, Wan-Bissaka, Fosu-Mensah, Maguire, Lindelof, Mengi, Bailly, Williams, Shaw, Fred, Matic, Fernandes, Pogba, Pereira, McTominay, van de Beek, James, Mata, Lingard, Greenwood, Rashford, Martial, Ighalo.