With roughly 24 hours left to choose which 30 players will be on a flight bound for Sydney, Australia, Don Mattingly said he’s “99 percent” certain on how to set the Dodgers’ travel roster.

Carl Crawford is out. His fiancee, television personality Evelyn Lozada, is due to give birth soon. MLB rules allow the Dodgers to place Crawford on the paternity leave list, which provides between one and three days for a player to attend to the birth of his child. Crawford could be re-activated for the Dodgers’ series against the San Diego Padres beginning March 30.

Mattingly said that who plays left field in the two games will depend on who’s pitching for the Arizona Diamondbacks. Scott Van Slyke is the favorite to play against left-hander Patrick Corbin, the Diamondbacks’ Opening Day starter. Since scheduled Game 2 starter Trevor Cahill is day-to-day with a knee injury, Mattingly wouldn’t venture to guess who starts in left field beyond Opening Day.

On the pitching front, Mattingly said that Dan Haren will not make the trip and Paul Maholm will. That still depends on the health of Clayton Kershaw, who starts against the Chicago White Sox tonight, and Hyun-Jin Ryu, who starts tomorrow against the Colorado Rockies. So long as both Kershaw and Ryu are healthy, Maholm is the favorite to start the Dodgers’ exhibition game against the Australian National Team next Thursday in Sydney.

The Dodgers and Diamondbacks get three “exempt” roster spots for players who will not play in Sydney, and then can be activated for their first regular-season game in North America March 30 in San Diego. Haren is one of the three as of now. Maholm could be another, then start the game against the Australian National Team, so long as Kershaw and Ryu are healthy.

How certain is all of this?

“We’ve pretty much decided,” Mattingly said. “Nothing’s been in stone for us just because of what could happen. Everybody that we feel like’s going to go for the most part, 99 percent, kind of knows that’s where we’re leaning at this point without any last-second stuff. The guys that we think are going to pitch over there know as of now.”

Mattingly added that three catchers will make the trip. A.J. Ellis and Tim Federowicz have been locks since camp began. Drew Butera is the only other catcher on the 40-man roster and seems like the favorite for the third job.