Andy Murray regrets the fallout and personal backlash he earned after posting a pro-Scotland message online.
Nadal, citing health concerns, will not play in the new round robin team format in Asia.
Former WTA No. 27 become's first female captain in country's history.
The 18-year-old American was diagnosed with Hodgkin's lymphoma prior to Wimbledon.
Players used social media in expressing their thoughts on the Chinese star's retirement.
18-year-old Australian, who won 2011 Wimbledon Girls title, announced an indefinite hiatus.
Cilic return to his hometown in Bosnia and Herzegovina for the first time since becoming a Grand Slam champion.