Charlton was involved in the home series against Japan 10 months ago and the away series win over the United States a few months later but isn't reading much into her Champions Trophy inclusion after then being dropped for the Oceania Cup in Australia late last year.
"I was fairly surprised to be included for this trip but I don't think it means much in terms of London Olympics because so much can happen between now and then. It's a great opportunity to get more international experience and show what I can do but I wouldn't see it as any great indicator because all the girls are after an Olympic spot."
Charlton is likely to see plenty of action at the Four Nations and in the practice games as Hager rests key players in the lead up to the Champions Trophy. They've been grouped with No2-ranked Argentina, eighth-ranked Korea and third-ranked Germany.
In and out of the side since debuting in 2010, Charlton knows what's needed to fight her way up the selection queue.
"I felt I went better as the [US] series went on last year but Mark's the sort of coach who is good with the players he doesn't pick. He's let me know what stuff he wants improved, which for me is to play more consistently and put on a strong performance whenever I go out.
"The opportunity is there to make an impression, particularly after the team went so well (in Amsterdam) last year because it would mean nothing if we didn't go out and do the same thing."
A revised Champions Trophy format from 2011 will see teams go from pool play to quarter and semifinals rather than round-robin points determining medal playoffs.