Crawley are missing Lewis Young, Thomas Verheydt and Dean Cox for their Sky Bet League Two clash against Chesterfield.
Right-back Young is expected to be out for a further two weeks because of his groin problem, but he has resumed running.
Ducth forward Verheydt is close to a return to first-team action as he nears a full recovery from his knee ailment.
Winger Dean Cox has an injured hamstring and the club are still waiting on a time-frame for his return.
Bradley Barry is expected to be fit for Chesterfield, despite almost swallowing his tongue in Saturday's defeat to Morecambe.
Defender Barry took a boot to the side of the head during the 2-0 loss and had to be helped by referee Darren Drysdale.
He continued, however, and should be passed fit for the trip to Sussex.
Jack Lester recalled Kristian Dennis and Louis Reed for the game and they earned the praise of the new Spireites boss. Lester confirmed goalkeeper Tommy Lee "is on the mend" and Sam Hird is fit to play.