That doesn't matter, as long as you show the will to play Davis Cup. You don't need to actually be in the team.
Looks like that is not the case. :shrug:
This is part of what I posted a few weeks ago on the Olympics ranking thread:
ITF's regulations regarding the Olympics say a player eligible for the Olympics must
"Make him/herself available for selection to represent his/her country in any of the International Team Championships of the Federation for two of the following years – 2005, 2006, 2007 or 2008 - provided that one of those years is either 2007 or 2008. In 2005, 2006, 2007 or 2008, a player who makes him/herself available for selection for one Tie in Davis Cup or Fed Cup will be deemed to have fulfilled the requirement for that year."
(
http://www.itftennis.com/shared/medialibrary/pdf/original/IO_21709_original.PDF)
Which puts participation of Moya and Ferrero at risk...as far as I am aware Moya hasn't played a DC tie after the 2004 final, and JCF has played only one tie since the beginning of 2005 and he just skipped the forthcoming tie in Peru (well it's his decision so you can't complain).
See how Sharapova has been so keen on playing for the Russian Fed Cup team since last year. It's all for the Olympics.
Or is it enough to just make themselves available for the selection, and not necessarily playing in the team?
Not the best time to be a player from countries that have many top players, is it. Of course that is provided he/she is willing to play in the Olympics. (Both Moya and JCF played in Athens, and JC played in Sydney too, so they know what's it like to play in the Olympics.)