The pair could have met at the last eight stage of the Monte-Carlo Masters, but Dominic Thiem denied a reunion between two multiple Grand Slam champions.
Nadal’s bid for an 11th crown in Barcelona is unlikely to be easy. He will open up the defence of his title against Andreas Haider-Maurer or Roberto Carballes Baena before a probable third round meeting with Kei Nishikori.
Djokovic, who accepted a late wildcard into the event in an effort to build momentum, will begin against Federico Delbonis or a qualifier and Feliciano Lopez is a possible last sixteen foe.
The player that emerges from the top quarter of the draw is projected to face David Goffin in the semi-finals.
In the opposing half of the draw, Grigor Dimitrov could encounter Philipp Kohlschreiber in the second round – if the veteran takes out Gilles Simon.
The Bulgarian, who is scheduled to meet Pablo Carreno Busta in the last eight, defeated the German on the Côte d'Azur earlier this week.
Dominic Thiem will attempt to bounce back from a heavy defeat to Nadal in Monaco against either Joao Sousa or Jaume Munar. Diego Schwartzman is expected to be his quarter-final opponent.
The action at the Barcelona Open, an ATP 500 event, begins on Monday. The full draw is available here.