Here is a look at what the rules look like and what the D-backs will need to do:
Cut the 40-man roster to 28
This is typically what teams do just before Opening Day, except they trim the roster to 25.
30 players travel
The D-backs will be allowed to take up to 30 players to Australia.
Players 26, 27 and 28
The D-backs will need to designate three of the 28 players who will not be eligible to play in the two games against the Dodgers.
Even if there is an injury, those three players remain ineligible. It is possible and even likely that these three spots would be the three members of the starting rotation who are not slated to start in the Dodgers series.
The players could still travel to Australia and play in exhibition games, or they could stay in Arizona to play in Minor League games.
Players 29 and 30
These players are eligible to play in the D-backs' exhibition game against Team Australia the night before the Dodgers series.
The two players are eligible to be added to the Opening Day roster if there is an injury.
The spots will most likely be non-roster pitchers who can eat up most of the innings in the exhibition game.
What about Cody Ross?
If injured outfielder Cody Ross is not ready to play in Australia, the D-backs could either bring him as one of the three ineligible players or place him on the disabled list.
If Ross goes on the 15-day DL, he will still be out when regular-season play resumes March 31. During the spring a club can typically backdate an injured player 10 days, meaning he would miss only the first five days of the regular season. Because the two games against the Dodgers are regular-season contests, Ross could be backdated 12 days and miss only three games against the Giants before being eligible to return.
What about the "Second" Opening Day?
The D-backs can shuffle their roster for the March 31 re-opener against the Giants.
To do so, they would need to option players who were on the 28-man roster they listed for Australia.
The D-backs can use players on their 40-man roster who were optioned to the Minors before Australia in the five exhibition games after the team returns from Sydney.
Disadvantage for D-backs?
Teams rarely play exhibition games the day before their season opener. However, with both the Dodgers and the D-backs required to play an exhibition game against Team Australia, one team was going to end up playing the day before the teams' Major League opener.
That team turned out to be the D-backs, who will play Team Australia the Friday before their Saturday opener, while the Dodgers play that Thursday and will have the Friday off.