Mariano Zabaleta will represent Argentina in place of Guillermo Coria in this week's Hopman Cup after Coria tested positive for a banned substance, officials said.
Zabaleta, 23, a U.S. Open quarter-finalist this year, is ranked 60th in the world.
His participation in the eight-team mixed doubles event, starting on Saturday at the Burswood Dome in Perth, Western Australia, was confirmed on Monday night, Hopman Cup director Paul McNamee said.
McNamee's bid to find a replacement player for Coria was hampered by civil unrest in Argentina, making communications difficult.
"Mariano actually approached me at the U.S. Open and asked if he could play but I had to say no because we'd already given a commitment to Coria," McNamee said.
"He's an excellent replacement. He's ranked 60th in the world, beat Sebastien Grosjean and Greg Rusedski at the U.S. Open and really is a very good player." <br />Americans Monica Seles and Jan-Michael Gambill will start as favourites in the international teams event.
World number one Lleyton Hewitt and 47th-ranked Alicia Molik will represent host country Australia.
Coria was suspended for seven months and fined $98,565 by the ATP last week after testing positive for the banned substance Nandrolone.
The 19-year-old was tested at the Open Seat Godo tournament in Barcelona on April 25 when he was ranked 30th on the ATP entry system. He is currently number 44.
According to the ATP, Coria's positive test came after he took a nutritional supplement.