Djokovic pulled out of the ongoing Miami Open due to an elbow problem but the world number two was named by playing captain Nenad Zimonjic when the team announcements were made on Tuesday.
However, with a busy claycourt schedule ahead of him – he is due to play in Monte Carlo, Barcelona, Madrid and Rome before May’s French Open - Nadal has not made himself available for the indoor hardcourt clash in Belgrade.
Roberto Bautista Agut, who has been troubled by an abdominal injury of late, is also missing from captain Conchita Martinez’s team.
She instead picks Pablo Carreno Busta, a new addition to the world’s top 20 following his run to the last four in Indian Wells last week, Albert Ramos, Marcel Granollers and Marc Lopez. Ramos returns to the team for the first time since 2013.
Martinez said: "We know how difficult it will be to play away from home again, against a team as strong as the Serbians, with a fast track and in favourable conditions.
"But I have every confidence in our players, who are having a great season."
Victor Troicki and Dusan Lajovic make up the Serbian side, who will now be favourites to advance to the semi-finals and a possible meeting with Great Britain.
In the opposite half of the draw, Nick Kyrgios will lead an unchanged Australian team against the USA.
The in-form Kyrgios was named by captain Lleyton Hewitt ahead of Tuesday’s nomination deadline, alongside Jordan Thompson, Sam Groth and doubles specialist John Peers.
It is the same quartet which saw off the Czech Republic in the first round.
Hewitt said he was expecting to face a “very strong” US team and highlighted Kyrgios, who has twice beaten Novak Djokovic in recent weeks, was key to their chances.
He said: “Nick’s obviously our number one player and we’ll be relying on him heavily to get us through the tie.
“He’s beaten a lot of quality players since our first-round tie against the Czech Republic and I feel the (outdoor hard) court in Brisbane is really going to suit him. He couldn’t be in better form and I really feel that he’s in the right frame to go out there and get the job done.”
The Americans are also unchanged. They have four top-30 singles players in their side - Jack Sock, John Isner, Sam Querrey and Steve Johnson.
David Goffin returns to the Belgium line-up for their home clash with Italy in Charleroi.
The world number 12 missed their first-round win over Germany but he joins the hero of that tie, Steve Darcis, in the team, along with Ruben Bemelmans and Joris de Loore.
Italy stick with the team that saw off holders Argentina in round one - Paolo Lorenzi, Fabio Fognini, Andreas Seppi and Simone Bolelli.
All four quarter-finals take place from April 7-9.
