Moses starred for an England side which reached the quarter-finals of the competition, scoring three goals.
Palace boss Peter Taylor is expected to use him regularly in the squad this season, but a thigh injury picked up on England duty means he'll be out of the side until October - starting with the Norwich game on Saturday.
"He can't kick a ball any long distance and will be out for four weeks, which is a bit frustrating," Taylor told the South London Press. "But we'll have enough bodies for Norwich and there are positives like Paul Dickov, who is starting to look more match fit."