Keegan even admits that Wright-Phillips will have to leave City eventually, and that the club would have to let him go if the right bid came in this January, but the City boss believes a move now could be too soon for him.
"He's 23 now and I don't think it would do him any harm to stay at Manchester City for another year or two," said Keegan.
"I went to Hamburg when I was 27 and was at my peak. Too many players have moved on too early and, when they have hit certain barriers, they haven't had either the maturity or the experience to get through them.
"Of course, every club wants Shaun - we know that - and it may well be that an offer comes in that is so big this club can't turn it down. But I would still fight that every bit of the way.
"I'm here for another 18 months, and I hope that Shaun will stay to help us build something at Manchester City. He's loved at City. He can't achieve all his ambitions with us, we know that, but he'll only be 25 in 18 months' time."
Keegan, who believes Wright-Phillips will be irreplaceable for the national team once given a start in major international, added: "Shaun is a very special player. I haven't seen a player like this in all my time in the game."