Croatia look set to finish second in Group A of the qualifying section, meaning they will then go into a play-off for a place in Brazil.
And Petric is hoping to be involved, having returned to first-team action with West Ham earlier this month.
Petric missed out on the previous national squads, but he puts that down to being a free agent at the time after he left Fulham.
"I definitely want to go to Brazil," he told T-portal.
"I didn't play for Croatia in their last matches just because I didn't have a club.
"But national team coach Igor Stimac has assured me that I would be part of the team if I'm going to play for my club."