The Norwegian international is making good progress in his recovery from a hamstring strain, but tonight's match against Gus Poyet's side comes a little too soon for the forward.
Rovers are also without Dickson Etuhu and Leon Best with knee injuries along with Adam Henley who is absent with a hamstring strain.
"This game probably comes a couple of days too soon for young Josh King," revealed Michael Appleton.
"This is a bit of a shame because I do think he is going to be a vital part of what we can do over the next couple of months.
"If we can get him right for this Saturday we will do but we'll bear in mind that the league is the most important thing.
"Dickson is still out and he'll probably be out for at least another month."
Rovers welcome back David Dunn and Markus Olsson to the squad after recovering from calf and hamstring injuries respectively.
The manager is expected to select from: Kean, Kane, Dann, Hanley, Martin Olsson, Vukcevic, Lowe, Murphy, Rochina, Kazim-Richards, Rhodes, Usai, Givet, Fabio Nunes, Dunn, Formica, Pedersen, Markus Olsson, Nuno Gomes, Morris, Goodwillie, Rosado.
Tickets for tonight's match against Brighton are available from just £15 for Adults, £10 for Seniors and £5 Juniors. Book online today at www.onerovers.co.uk
and collect your tickets from the Blackburn End collection point on the day of the game.
Supporters who bought a half season ticket are reminded that this game is not included in their package and that a separate ticket will need to be purchased.