Hughes believes that the form shown by Stoke's player of the season should have at least earned the centre-half some attention from the England boss.
With doubts still cast over the fitness of Phil Jagielka and Phil Jones, the lack of communication with Shawcross has left Hughes even more baffled.
He said: "Ryan's had an exceptional season and has been one of the mainstays of our team.
"There are very few centre-halves I've seen this season who are head and shoulders above him.
"I find it difficult to comprehend that he doesn't get a mention for England or even that someone doesn't come with the specific job of watching him."
Shawcross won his only cap when he came on as a substitute in England's 4-2 friendly defeat to Sweden in November 2012.
Hughes thinks that by not including him Hodgson is leaving behind a player that he could rely on.
He added: "Maybe it's due to the change in management staff that he's not featured. I don't know. But if he was picked, he wouldn't let anyone down - and he'd be a great tourist."