The British No.1 was laid low by a virus on Wednesday evening and was unable to attend the draw ceremony yesterday.
Leon Smith, the captain, remained hopeful his star player would be able to play today and Murray did make it to Tennis Club Napoli late in the afternoon.
The draw gives Murray a bit of extra time to recover, with James Ward playing the first singles rubber against Italian No.1 Fabio Fognini. Ward was given the nod over the higher-ranked Dan Evans by captain Leon Smith. The Londoner's selection was not a surprise, given his stunning win over the USA's Sam Querrey in February, which helped Britain to a first World Group victory in 28 years.
Evans was replaced in the four-man squad by Ross Hutchins, leaving Smith's options open for what could be a crucial doubles rubber tomorrow. Plan A is for Murray to team up with fellow-Scot Colin Fleming but, if it is felt that is too much for the Wimbledon champion, Hutchins will make his first Davis Cup appearance since his fight against cancer.
Italy went into the tie as favourites even before the news about Murray's illness emerged. Britain upset the United States on clay but, in the absence of the injured John Isner, the surface ended up hampering the home side more than Smith's team.
The Italy team, on the other hand, is very much at home on clay and in world No.13 Fognini they have one of the season's strongest performers. The talented, but unpredictable, 26-year-old already has an ATP Tour title and another final appearance on the surface in 2014, but he is still affected by a thigh problem he suffered in his defeat by Rafael Nadal in Miami last week.
Seppi, ranked 34th, is a different type, solid and reliable from the back of the court - and it is a big ask for Ward to upset either player.
Great Britain have won eight of the nine ties they have contested since Smith, Murray's coach as a junior, took over as captain in 2010, his reputation becoming further enhanced with each win.
He said: "As usual, there's a very good team spirit. We get on great and we've had a good time, but it's also been very business-like. We believe we can win, which is important. We really feel that we've earned the right to be here. There's a few challenges: they've got a very strong team; obviously we're away from home again and I think the crowd will play a part; and the surface. But I think we're strong enough mentally and we've got enough quality to put up a really good fight."
Murray has struggled to rediscover his best form this season after back surgery, but one of his best weeks came in San Diego and the 26-year-old appears highly motivated to do well in Davis Cup. There were promising signs in Miami last week, but his quarter-final loss to Novak Djokovic dropped him to eighth in the world rankings, his lowest spot since 2008. Beating Fognini would be one of his best wins ever on clay.
The venue, meanwhile, does not hold happy memories for Murray, who recalled losing in qualifying at a lower-tier event when he was a teenager. "I didn't remember I'd been here and then when I turned up to the club, I was like, 'I'm sure I played on that court'," he said. "I was probably 16 or 17."