Cahill was among 32 players picked in an expanded training squad, announced by coach Bert van Marwijk on Monday, but the veteran forward faces an anxious wait before knowing whether he will make the final cut for Russian Federation.
The coach will then reduce the squad to 23 on June 3, which is the maximum number a team can take to the Cup.
The 38-year-old Cahill is Australia's all-time leading scorer with 50 from 105 internationals, but he has struggled for form and match time in recent months.
"A lot of time he is captain of his team despite being 21, and playing in the highest level in Croatia", van Marwijk said.
For the past nine months or so, Football Federation Australia staff have attempted to coax Karacic to switch his worldwide football allegiances from Croatia - who he has represented at youth level - to his father's country of birth.
"He's a very good striker (but) he doesn't play and I have to take a decision on whether to take him to the world championships".
Socceroos coach Bert van Marwijk was a keen spectator for the A-League grand final.
"I understand that there will be change and that (it) is also in the (World Cup) but I don't think that we don't discuss anymore situations when we have a video referee". "He's not 19 like Arzani - he's two times that age - but he's also a player who can make a difference".More news: "Beersheba - Eilat": Elia Viviani won the second stage in a row
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Arzani, who is regarded as one of Australia's brightest young prospects after helping Melbourne City win the A-League, also made the provisional squad.
Despite starring for Australia at previous World Cups, Cahill - at the age of 38 - was in some doubt to be named.
Van Marwijk stuck with the experienced core of players who guided the Socceroos through the long qualifying phase, and produced one surprise by picking uncapped defender Fran Karacic. Karacic holds an Australian passport, although he's never actually visited the country before.
Coach Bert Van Marwijk revealed 19-year-old Melbourne City flyer Arzani and 21-year-old Croatian based right-back Karacic would be part of the initial squad for Russian Federation at a press conference in Sydney on Monday.
"Everybody knows that the right defending position, I don't have a lot of choice for that position", van Marwijk said.
The 65-year-old's selection featured all 26 players on duty for the most recent friendlies against Norway and Colombia, including big names such as Matt Ryan, Aaron Mooy, Tom Rogic, Matthew Leckie and Robbie Kruse.
At 185cm tall, he can also play other defensive positions along with right midfield but is viewed by the Australian camp as a solution for the problem right full-back position.