McCarthy has spent much of his career in the lower leagues, including loan spells in non-league football.
But now it appears the work he has put into his career is being rewarded at the Saints. And McCarthy wants to take advantage of his third England call up.
"I wouldn't say it puts more pressure on me," McCarthy said to the Daily Echo on competing for an England place.
"I think, at the end of the day, I sort of concentrate on what I've got to do.
"Obviously I've been called up for a reason and there's now four of us here, but it's a time for me to go out there and prove what I can do.
"We're away for seven or eight days, so it's enough time to sort of show him what I can do.
"And at the end of the day, I want to give him a decision to make.
"Obviously it's an unbelievable feeling to be back here.
"I've been in two squads before but that was quite a while ago, so obviously after the World Cup and everything that has gone on it's been a positive for English football.
"It's nice to be back involved and a part of it."