Source: Team_Talk
Eagles put Butterfield up for sale
The 29-year-old defender was shipped out on loan to Championship strugglers Charlton in March and has not been a regular in the Eagles line-up since the emergence of youngster Nathaniel Clyne.
Warnock told the Croydon Advertiser: "We will listen to offers for Danny in the summer - but in saying that we will listen to offers for all of our players.
"But if we get an offer for a player I want to keep hold of then I will reject the offer."
Butterfield has been at Selhurst Park since the summer of 2002, making him Palace's longest serving player, and has made nearly 200 appearances for the club.