Maria Sharapova failed a dope test for the drug meldonium at the 2016 Australian Open and was suspended for two years by ITF.
Roger Federer and Rafa Nadal defied odds in January to reach the final of the Australian Open.
Toni Nadal will step down as Rafael coach after this year's ATP Tour, as he feels he has been sidelined by other figures in the player's entourage.
The ITF said that Arnaud Gabas had undergone a successful surgery to repair a fractured eye socket.
Grigor Dimitrov has climbed back up the ATP rankings to 13th.
United States Tennis Association has apologised after version of the German anthem associated with the Nazi era was sung by the soloist.
The second reverse singles in Czech Republic against Spain pits Barbora Strycova against Lara Arruabarrena.
Timea Bacsinszky downed Alize Cornet 7-5, 6-4 in the opening match, to give the host's a flying start.
Garbine Muguruza defeated Barbora Strycova 6-0, 3-6, 6-1 in the opening singles to give Spain a 1-0 lead over Czech Republic.
Nine players and officials were sanctioned by the Tennis Integrity Unit in 2016, the most in a single year since the body was created in 2008.
Tournament director Richard Krajicek says he tried unsuccessfully to get Roger Federer or a top-five ranked player to replace Rafa Nadal.
Fabio Fognini made his experience tell to beat Guido Pella in five sets and send Italy into the Davis Cup quarter-finals.