Both Alan Smith and Danny Mills are attracting interest, although chairman Freddy Shepherd has refuted rumours of a joint £6.5m bid.
He said: "The end-of-season meeting with Sir Bobby Robson about players for next season has not even been held yet."
Newcastle are known to be looking for a long-term replacement for Alan Shearer, who has already announced his intention to retire at the end of the 2004/2005 season.
Robson is also after some defensive cover, with Mills tipped to reunite with former teammates Jonathan Woodgate and Lee Bowyer.