Roy Hodgson has called up fit-again Ruddy for the matches against Moldova next Friday and Ukraine the following Tuesday, along with Hart and Celtic's uncapped Fraser Forster.
The England manager has backed Hart despite the goalkeeper being blamed for his part in Manchester City's shock 3-2 defeat by Cardiff on Sunday and being at fault for the first goal as England beat Scotland 3-2 earlier this month.
Hughton, however, insists Ruddy, who missed a large chunk of last season when he underwent an operation on a thigh injury, is in the sort of form to put real pressure on Hart.
"Any player that goes on international duty is there on merit and to challenge and to play," Hughton.
"If I look at the progress he has made over the last few seasons he has the capabilities to really push for a place.
"It's early in the season but if I look at the reaction from a disappointing season for him last season, at least the last two thirds of the season with the injury, he has made a full recovery from that and at the moment is back to where he was before the injury.
"I think he has done well and has put himself in position to put pressure on the position. And that's how it should be. Anyone who is involved in an international squad should be there on merit and feel they can put real competition on that position.
"He's a big personality, a big frame, and his performances for us over the last few seasons have very much warranted him being in that international squad."