JAAP Stam fears Premier League clubs could make moves for Reading FC's star players in the summer should they fail to secure promotion.

The Dutchman admitted top players like Liam Kelly, Liam Moore and John Swift have all made remarkable progress under his leadership this season and could attract bids from top-flight teams.

And Stam insisted he would understand if Royals decide to cash-in on some players, providing the money can be used to re-invest in his squad.

Last summer Royals lost the likes of Oliver Norwood and Aaron Tshibola, who made big-money moves to Brighton and Aston Villa respectively.

But Stam used the cash to secure the likes of Moore from Premier League champions Leicester City for £1.5m, Swift from Chelsea on a free and Tyler Blackett from Manchester United for around £1m.

All three have played a massive part in Reading's stellar season after finishing third in the Championship table, and Sta knows his players' performances will not have gone unnoticed.

"I do worry about teams coming in for players," asserted the 44-year-old Dutchman. "If you want to make steps as a club then you don't want to sell your best players.

"But if you do sell them you have to think if you can buy other players back. Maybe not with the same quality, but with lots of potential.

"Liam Kelly for example, you're always worried if you have good players then they could go.

"This season lots of players have stepped up and they have shown themselves in the league.

"There will be a lot of interest from other clubs, so you always worry if that player is going then can we bring someone else in or do we have players in the youth team who can step up?

"It's not always the case so it is very important that if someone goes - and I can understand that because as a club sometimes you have to sell players to bring in extra money - then you can spend that money."

First-team players like Garath McCleary, Player of the Year, Ali Al-Habsi, and 18-goal hit-man Yann Kermorgant all signed contract extensions this year.

However, USA international Danny Williams is yet to commit his future to the club, and could leave Reading on a free after the play-offs.

And Stam revealed he has no idea why the deal is stalling.

"Brian Tevreden and the club have both spoken to Danny," he concluded. "Brian has spoken to him about signing a new deal.

"It's not only about the club though, it's also about the player and what he wants to do."

When asked if negotiations had stalled over Williams' wages, Stam retorted: "I don't know, you would have to ask Danny himself."

Meanwhile, Royals captain Paul McShane and McCleary both face late fitness tests before tomorrow's Championship play-off semi-final first leg against Fulham at Craven Cottage (5.30pm ko).