Portsmouth centre back Matthews' hopes of selection for the June 11 to July 19 World Cup are likely to be over following an ankle injury, media reported.
Dylan Leonard, who plays for German club Schalke 04, earns his first call-up to an Australia squad.
Leonard joined 12 additions to the training squad in Sarasota, including defender Gianni Stensness, who returns to the squad for the first time since October 2024.
The new arrivals join 19 players already in camp ahead of coach Tony Popovic picking his final 26 for the World Cup.
Cameron Devlin, Martin Boyle and Ante Suto joined from Scotland, while Jacob Italiano, Jason Geria, Milos Degenek, Aiden O'Neill and Jordan Bos were also added.
Australia play Turkey, the United States and Paraguay in the group stage at the World Cup.