For the second time in Open Era, Team USA will start two rookies in a Davis Cup tie.
The Spaniard will work on a trial basis with the former coach of Victoria Azarenka and Eugenie Bouchard.
Before hosting Australia in this weekend's Davis Cup semifinals, Team GB gets its kicks on soccer pitch.
The Czech star rises to No. 5 in the world but will need time to recuperate.
"Of course I will not be a player anymore in the future, but I would love to be involved in tennis," US Open champion says.
"I am at the peak of my abilities and I want to keep going exactly the same way," world No. 1 says of quest for more Grand Slam titles.
Relive title triumphs of every 2015 US Open champion in this one-minute recap.
