"We want to offer Bernard the opportunity to raise the issues he has raised, so we can address those with him," TA president says.
Americans to travel to Uzbekistan for Sept. 18-20 World Group playoffs.
German tennis star now being helped by Novak Djokovic's coach.
Former No. 1 is top seed at this week's Istanbul Cup.
Serena Williams became the oldest No. 1 in WTA history in February of 2013. Two years later, she's still top dog.
Maria Sharapova, Serena Williams, Donna Vekic, Kristina Mladenovic and Monica Puig enjoyed R & R at the beach.
World No. 10 set for Hamburg return next week, seven years after he beat Roger Federer to win the title.
