The Irish midfielder suffered a knee injury in training after colliding with goalkeeper Casper Ankergren.
Boss Gus Poyet revealed Dicker has not suffered any ligament damage, but he will not be ready in time for the weekend.
Poyet can welcome back Lewis Dunk into his squad after the defender served a one-match ban in the 2-2 draw with Charlton last Saturday.
Right-back Bruno had to come off at The Valley with an Achilles problem but he will be in the squad.
Fellow Spaniards Andrea Orlandi (broken rib) and Vicente (thigh) are still missing although the latter is stepping up his training as he bids to be available for the first time since August.