Right-back Sean Long may fill in, while on-loan Brighton winger Joe Ward is not eligible to face his parent club.
Brighton striker Glenn Murray is available to return after suspension, while full-back Liam Rosenior could feature after a long-term ankle injury.
Left-back Gaetan Bong (knee) is out, but captain Bruno (groin) and striker Sam Baldock (calf) will not be risked.
England Under-20 defender Fikayo Tomori could make his debut for the Championship table-toppers, after joining on loan from Chelsea.
Lincoln manager Danny Cowley told BBC Lincolnshire:
"They are top of the Championship and we said going into the Ipswich game we would need to climb a mountain to overcome that challenge and this is probably like getting to the moon. It will be a tough ask.
"It is a massive day for our players. For most of them this will be the biggest game of their lives, and the biggest examination of their football careers.
"Brighton have an unbelievable squad, with incredible depth, and have two teams that could compete successfully at Championship level. That is probably the reason why they are having such a successful season."
Brighton boss Chris Hughton told BBC Sussex:
"It is a big game and probably become an even bigger one because of Lincoln's exploits in the last round.
"We have to prepare exactly the same as if it is a Championship game. We didn't do so well in our last away game [losing 2-0 at Preston] so we know what can happen.
"If we needed an example of how good Lincoln can be, most of our focus has been on that Ipswich game. In both the games against them, Lincoln were very good.
"We know how tough it can be so we need to make sure we do the best we can."
National League leaders Lincoln could be without left-back Sam Habergham (dead leg) for their FA Cup tie.