West Ham coach Kevin Nolan says he would not sell Declan Rice for £100m.
The England international is thought to be a Manchester United transfer target ahead of next summer.
The Red Devils lack a top-class holding midfielder and are said to have identified Rice as the player they want in that position.
West Ham value their academy product highly, though, and his current contract runs until 2024.
The Hammers even have the option to extend that deal for another 12 months, giving them a sense of control over the situation.
United will have to offer big money to prise Rice away from east London, as Nolan indicated in an interview with BBC Sport.
"When you're in the room with Declan Rice, you know you're in the room with Declan Rice, but he doesn't make you feel uneasy.
"He's one of those kids who wants to learn, wants to get better, always willing to take advice on, always willing to try and get better and want to get better.
"The biggest thing for me as a coach is he listens to me, he respects me for what I've done, but I feel that this lad can go on and I feel he's already done more than I have in terms of England appearances, being in Europe and things like that.
"He's going to keep going because his athleticism. He trains every day, he wants to train every day, he can hit it from one side of the pitch [to the other] with his right foot or his left foot.
"He can run with the ball, he's got everything that you could possibly wish for as a footballer and plus he's got a good footballing brain where he's now learning for West Ham, and he's done it with England, he's now learning how to control games.
"When you watch him play, he just seems in control of everything. For me, he's going to get better. Putting a price tag on him, I wouldn't sell him for £100m."
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