Mark Philippoussis has been ruled out of Australia's Davis Cup quarter-final against Argentina this month because of an ankle injury, with Peter Luczak called into the team to replace him.
World number two Lleyton Hewitt and Davis Cup veteran Wayne Arthurs will likely shoulder most of the burden after the loss of Philippoussis and the retirement of record-breaking doubles player Todd Woodbridge.
The 28-year-old Philippoussis had not recovered from the ankle tendon injury he suffered during Wimbledon, Australia's Davis Cup captain John Fitzgerald said on Tuesday.
Philippoussis, a former Wimbledon and U.S. Open runner-up, has slumped to 208 in the rankings and was beaten in the second round of Wimbledon last month by Russian Marat Safin.
Fitzgerald has now turned to Australia's third-ranked player, world number 147 Luczak, for the tie, to be played on grass at the Sydney Olympic tennis centre from July 15-17.
Luczak comes in alongside world number 183 Chris Guccione, who made his first Davis Cup appearance in Australia's 5-1 defeat of Austria in the first round in March.
"With Todd Woodbridge's recent retirement from tennis and Mark Philippoussis not fit, the door has opened for Peter Luczak and Chris Guccione to step up into the Australia side," Fitzgerald said.
Australia faces a difficult tie against an Argentina team including world number 10 David Nalbandian, number 12 Mariano Puerta and 15th-ranked Guillermo Coria.