Brown suffered an ankle problem in last weekend's 1-0 win against Tranmere but it is a knock sustained in training which is likely to rule him out at the Withdean Stadium.
Director of sport Chris Turner hopes he will be available for next weekend's FA Cup clash at home to Kettering.
Ben Clark made his comeback from hernia and groin problems in the reserves' 4-2 defeat at home to Rotherham on Wednesday and he could make the bench, as could Colin Larkin who has recovered from a groin injury.
However, assistant manager Colin West admitted fringe players such as Leon McSweeney and Jon-Andre Fredriksen did little to enhance their first-team claims in the second-string defeat.
He said: "There was an opportunity for some of the lads but they didn't really knock a door down."
