Liverpool, Manchester United and Arsenal are ready to start the auction.
Robbie Elliott: "Perez is obviously a handful.
"He's one who hopefully we can keep hold of, because being young I'm sure there'll be people looking at him and seeing how well he's done.
"There's three or four players who I think have had a good season. It [losing them] is a risk for most clubs, never mind Newcastle.
"I think Colback has done well and [Moussa] Sissoko on his day is one of the best players at the club,
"Better players are going to be wanted by better clubs challenging for trophies, players want that.
"It's only natural that if clubs like that come along then players are going to want to listen."