Shawcross has just made one appearance for England, back in 2012 against Sweden, and Hughes is baffled by his constant exclusion.
Hughes told Sky Sports: "Why he isn't involved at England level, once again I have no idea."
"OK, they may look at the fact and say that he hasn't played enough football this season because of his injury, but even before that when he was performing exceptionally well he wasn't getting a look-in."
"Since I've been here, he's been absolutely outstanding. There aren't many defenders like him in the game, I have to say."
"Obviously Jack Butland is involved in the England set-up, so maybe he will be able to put in a good word for him and he'll be involved in the next one. Don't hold your breath, mind."