The former U.S. Open runner-up owns 35 titles between singles and doubles.
World No. 2 hasn't officially retired from Swiss Davis Cup squad.
The Spaniard will take over for Manolo Santana in 2019.
Team Canada also has a new captain for 2018.
Torben Beltz coached Angelique Kerber to two Grand Slam titles.
Rafa golfs righty for a good cause.
Kei Nishikori turns 28 on December 29th, but already felt advancing age.
