Eagles eye Gallas swoop
However, Holloway admitted there had only been initial talks with Gallas.
"We are a long way off a deal with him, but I met him. Whether we can ever come to a deal I do not know," Holloway said at a press conference on Sky Sports.
"He was a very nice man and he admitted he is only 50 per cent fit, which might be a problem."
Palace are in the market for new bodies to bolster the squad, with Holloway confirming permission had been given by Reading to speak to winger Jimmy Kebe.
"He is one of the ones we are trying to pursue," the Eagles boss added.
"I was allowed to speak to Jimmy at about half 11 on Wednesday night, so I don't know where we are with that."
Palace, promoted after winning last season's Championship play-off final, have also been linked with a loan move for Tottenham England under-21 midfielder Tom Carroll, as well as permanent deals for Aston Villa's Scotland international Barry Bannan and West Ham's out-of-favour Portugal forward Ricardo Vaz Te.
The Eagles are at home to Sunderland in Saturday's 5:30pm kick off, but look set to again be without injured midfielders Jerome Thomas and Yannick Bolasie.