Neither Rafael Nadal nor Spanish captain David Ferrer would say Monday whether the 22-time Grand Slam champion will play singles or doubles — or even at all — at the Davis Cup Final 8, his last event before retirement. Spain is scheduled to face the Netherlands on Tuesday in the quarterfinals on an indoor hard court at the Palacio de Deportes Jose Maria Martin Carpena. Asked at a news conference how he has been feeling in practice in recent days and whether he is ready to play, Nadal said: “That’s a question for the captain.”