London - Novak Djokovic and Milos Raonic were left out of their countries' Davis Cup quarter-final squads on Tuesday but Andy Murray was confirmed to lead Great Britain's push for a first semi-final spot since 1981.
Serbia captain Bogdan Obradovic didn't name world number one Djokovic in the squad to travel to Buenos Aires to tackle Argentina, opting for Vicktor Troicki, Janko Tipsarevic, Dusan Lajovic and Nenad Zimonjic.
However, Djokovic insisted he still hasn't made up his mind over the July 17-19 tie.
"There is a possibility that I'm still going to be on the team. There's a possibility. But it's still not final, as he has, by the rules, the position to change the team a few days before the match," said Djokovic at Wimbledon on Tuesday where he reached the last-eight.
"Even though I'm not in the team that he entered, I still may be there."
Argentina announced their team to play Serbia last week.
In the absence of injured Juan Martin del Potro and Juan Monaco, the number one player will be Leonardo Mayer with Diego Sebastian Schwartzman, Federico Delbonis and Carlos Berlocq making up the remaining spots.
Murray will lead Great Britain's team against France in the last-eight at Queen's Club.
World number three Murray was named on Tuesday in the squad for the tie against last year's runners-up. It's the same squad which defeated the United States in the first round of the World Group.
Murray, who will be playing in the Wimbledon quarter-finals on Wednesday, is joined by James Ward, fresh from his run to the third round at the All England Club, with Jamie Murray and Dominic Inglot likely to play doubles.
France captain Arnaud Clement has opted for grass-court form in his quartet.
Gilles Simon and Richard Gasquet, who are also in the Wimbledon last-eight, are joined by Jo-Wilfried Tsonga and Nicolas Mahut.
Australia, in turmoil over the exclusion of Bernard Tomic and Nick Kyrgios's controversial 'tanking' in his Wimbledon loss to Gasquet, face Kazakhstan in Darwin.
New coach Wally Masur announced Monday that Kyrgios, Sam Groth, Thanasi Kokkinakis and Lleyton Hewitt will form the side looking to reach the semi-finals for the first time since 2006.
Kazakhstan kept the same squad which defeated Italy in the opening round for the quarter-final trip to Australia.
Mikhail Kukushkin, Aleksandr Nedovyesov, Andrey Golubev and Dmitry Popko are the men in the squad.
Belgium face Canada in Ostend with world number 15 David Goffin, Steve Darcis, Ruben Bemelmans and Kimmer Coppejans.
Canada will be without world number eight Raonic who has yet to recover from the foot injury which ruled him out of the French Open before he returned for Wimbledon where he lost in the third round to Kyrgios.
Frank Dancevic, Daniel Nestor, Filip Peliwo and Wimbledon quarter-finalist Vasek Pospisil were named in the squad.
"I'm devastated not to be participating in this tie against Belgium," said Raonic.
"Due to my recurring injury, I am not able to play tennis for the next few weeks."
In Europe/Africa Zone Group I, new Spain captain Conchita Martinez has named her first side since taking over on Monday.
David Ferrer, Pablo Andujar, Marc Lopez and David Marrero are in the squad for the long trip to Vladivostok to play Russia.
But Rafael Nadal, who has been critical of Spain's internal politics as well as the original appointment of female coach Gala Leon to the Davis Cup team, was not included.