Ledesma, who took over the top job ahead of the 2018 season, named a 29-man squad for a preseason trial against the Bulls and their opening Super Rugby clashes against the Stormers and Lions.
The former Wallabies scrum coach has named rookie propr Javier Diaz in the team, replacing Santiago Garcia Botta.
Flanker Pablo Matera will skipper the side, with Joaquin Tuculet and Tomas Lezana the vice-captains.
Ledesma said his first round of selections was the most difficult.
“Always, the first list is very difficult. It's a complicated moment to have to leave players out ,” he said.
“Everyone who goes to South Africa can play. The inclusion of Javier Díaz is because Santiago (García Botta) can not do it. For the next lists they will be taken into consideration and other factors will be taken into account.
Ledesma said he was pleased with the progress the team had made in the preseason.
"It's a group that came with a lot of desire to work, with enthusiasm and joy,” he said.
“It is an easy group to live with, easy to train. We can all look each other in the eyes, be authentic and I am very happy to be with this group of people.”
The Jaguares fly to South Africa later on Wednesday, Australian time.