"I have been playing professionally since I was 18 at right-back, so to go to your first World Cup and probably not play in your preferred position... is... well, not disappointing but a little bit of a step back," Walker told British media.
"I have to move on from it... as long as the manager feels it is going to benefit the team, then why not?"
Walker, who was an integral part of a City defence that conceded the fewest goals in the Premier League last season, outlined the importance of reading the game as a centre-half.
"It is about reading the game, I don't want to leave space at the back to get on a counter-attack," he added.
"I'm a defender first and foremost, and if I'm playing right centre-half I am even more of a defender than the wing-backs".
England will also face Panama (June 24) and Belgium (June 28) in the group stage.
(Reporting By Arnab Paul in Bengaluru; Editing by Amlan Chakraborty)
