He is currently training with Palace and manager Neil Warnock confirmed his interest in securing the Australian defender on a contract.
"Kisnorbo is training with us," Warnock told the Croydon Advertiser.
"We will have to act quickly if we want him because there are a couple of other clubs who are interested. He is a smashing lad."
Meanwhile, new Palace signing Darren Ambrose insists he should not be considered a replacement for Ben Watson, who left the club for Wigan Athletic in January.
Ambrose, whose dead-ball ability has been likened to Watson's, said: "Ben is a fantastic player, but I'm not here to replace anyone. I'm here to play my own game.
"As I say Ben is a quality player, he showed that with the move he got last season.
"But I'm just concentrating on myself and adding my qualities to the team."