McCarthy will meet up with the England team for the first time on Sunday after being the surprise inclusion in Roy Hodgson's squad for the upcoming friendlies against Republic of Ireland and Brazil.
The call-up was the latest event in a remarkable rise for the 23-year-old, who just five years ago was playing non-league football with Team Bath.
McCarthy was not even first choice with Reading at the start of the season and he ended the campaign with just 13 top-flight appearances to his name.
Reading's relegation to the npower Championship could have lessened his chances of a regular place in the Three Lions squad, but Hodgson has called up Football League players before - like Crystal Palace man Wilfried Zaha - and Pearce thinks playing in the second tier should be no barrier for the talented stopper.
"I just think he needs to be playing. If he is playing Roy will look at him," the England Under-21 coach said.
"You hear some people talking about how players from fashionable clubs only get the opportunity (at international level), but he has proven that idea wrong. If you are playing well enough you will get the opportunity no matter where you are.
"He is in the England squad now so that tells you something straight away - he wouldn't be in the England squad if Roy didn't trust him."