The Eagles have won only one of their last four games, their most recent outing ending in a 4-0 league humiliation at the hands of Sunderland on Saturday.
Schlupp, who completed a four-and-a-half-year deal to Selhurst Park last month, picked up an injury in the 3-0 loss to Bournemouth last week, forcing him out of Saturday's defeat.
“Jeffrey should be fit soon and Luka has to get a permit to get back into the country," Allardyce said, as reported by his club's official website.
"Momo [Mamadou Sakho] needs a bit of catching up in his fitness as he hasn’t played a first-team game.
"Hopefully, they will make a difference and help lift the rest of the players.
"We have a lot of work to do with providing these players with the right positive mental attitude to go out and perform here on this ground.”
Schlupp has made two league appearances for Palace thus far.
According to Allardyce, in a separate interview, the Ghanaian is expected to be available for Saturday's clash with Stoke City at the Bet365 Stadium.