Talk of 'wow' signing has us all wondering, with owner Mike Ashley said to be ready to splash the cash.
Argentina star Javier Saviola has been mentioned but Keegan obviously played it down.
But we hear from Spain his target is Thierry Henry.
Keegan: "Too often in the recent past we have bought players who have not been quite good enough," he said.
"They have either not settled or not understood what it means to play for Newcastle.
"You can't just say good players can play at Newcastle because history will prove they cannot.
"I don't think it has been a bad summer but then I have not been reading what has been written.
"But in football at the moment, you don't want these things on your doorstep, at your club.
"It is nice to get a good result so it goes on to another club but I don't envy whoever it is."
Sir Alex Ferguson was said to be set to make a move for Thierry Henry, but while the Jock is considering his options, Newcastle could step in.
Injuries and illness have left the Premier League champions short up front, and Ferguson is confident of signing Dimitar Berbatov of Tottenham Hotspur, although Henry has emerged as an intriguing alternative.
Although Henry has played down talk of a move away from Barcelona, he is far from happy in Spain, playing ionly a bit-part in Barca's failed title challenge last season.
Whether reports of United's apparent interest in Henry are merely intended to make Tottenham sweat - especially because the North London club are likely to need the money from Berbatov to sign another striker - is unclear, but Mike Ashley is said to be willing to back KK.
Keegan said last May at a talk-in: "If I could sign anyone in the world, I'd have to say it would be Henry."