The Championship leaders have confirmed that the pair are set to miss the rest of the year.
Rosenior had to be replaced midway through the first-half of the Seagulls' victory over Birmingham City last weekend, and The Argus report that the club have now confirmed that the 31-year-old has sustained medial ligament damage to his right knee.
The former Hull City full-back has been integral to Chris Hughton's side this season, helping the Albion remain the only unbeaten team in any of the top four divisions.
Meanwhile, LuaLua has had to undergo minor surgery following a setback in his recovery from a groin injury, The Argus report. The exciting winger made an excellent start to the campaign with four goals coming in nine appearances in all competitions, but has not featured since September.
With six games ahead before the end of the month - including fixtures against fellow promotion-chasers Middlesbrough, Derby and Ipswich - Hughton could have certainly done with having two of his key men available to him.