Martyn was recently linked with a move to Southampton, but that has fallen through, and the player intends to try and reclaim his place as the number one.
"Not going on the trip has cost me my place - and I've got to try and win it back."
Until he does though, he's under no illusions that his England career may be placed on hold.
"I don't think I have a hope of playing for England while I'm not in the Leeds United first team.
"I'd have thought that I'd have to be playing regularly at first team level for me to be even considered at international level."