Gibson suffered a knee injury in the pre-season friendly against Real Betis last month while Alcaraz is recovering from a hernia operation.
Martinez said: "Darron and Antolin are in training with the first team.
"Now it is a case of getting the match fitness. That could take a couple of weeks, depending on how they react.
"Darron and Antolin won't be fit for the weekend but they are not going to be too far away. For Darron, in a couple of weeks, he'll be getting really close."
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