Shawcross has won two caps for Stuart Pearce's under-21 international team, but his reputation has grown considerably since his club were promoted to the Premier League.
After an impressive debut season in the top flight, the 21-year-old has continued that form in the opening four matches of this campaign and has already been linked with former club Manchester United and Liverpool.
Pulis, however, is determined to hang on to a player whom he believes could soon be challenging for a centre-back place in the England team.
"I have no doubt about it that one day Ryan will play for England,'' said the Stoke boss. "It isn't just the fact that he is big, but he is also extremely fast and I think that is vital if you are to go on and play for your country at the highest level.
"We brought him here as a relatively unknown player, I don't even think he had played that many games for Manchester United's reserve team.
"The amount he has come on over the past few years is unbelievable really, but he knows he has to keep his head down, keep on working hard and keep on doing the things he is doing.''
Pulis admits speculation about the player's future can be distracting but he has told Shawcross he is a pivotal figure in the future of Stoke.
"Ryan is an important part of what we want to achieve here,'' he told stokecityfc.com.
"He is an exceptionally talented kid who has a big part to play at this football club.''