The Hopman Cup will be without one of its biggest drawcards after Frenchman Jo-Wilfried Tsonga was forced to withdraw because of an ongoing arm injury.
But big-serving American John Isner will be back after Jack Sock became another late scratching because of hip surgery.
Sock will also miss the Australian Open.
Tsonga teamed with Alize Cornet to win last summer's Hopman Cup.
The flamboyant Frenchman is a crowd favourite throughout the world, and his absence is a big blow to the mixed-teams tournament, which starts at Perth Arena on January 4.
It's unclear whether the arm injury will affect Tsonga's participation at the Australian Open.
World No.24 Benoit Paire will replace Tsonga, but France will find it tough to defend their title against a powerful American team featuring world No.1 Serena Williams and Isner.
Isner won the Hopman Cup alongside Bethanie Mattek-Sands in 2011, but knee and ankle injuries have plagued him on his last two visits to Perth.
"I always like playing in Perth. It's the perfect start to the year and I always have a great time on and off the court," Isner said.
"It's not good to hear Jack is battling injury and I hope he gets well soon."
Paire's inclusion sets up a mouthwatering re-match against rising Australian star Nick Kyrgios.
The pair faced off in an epic second-round battle at this year's Australian Open, with 25-year-old Paire recovering from a two-set deficit to notch the win.
Kyrgios will team with Casey Dellacqua as Australia attempts to end their 16-year title drought.
