World number one Andy Murray will face a wildcard in his opening match at the Madrid Masters.
The world number one - who finished as runner-up to Novak Djokovic in last year's final - has received a bye through to the second round, but he will play a wildcard early next week.
The three-time Grand Slam winner has been drawn in the same half of the draw as Stanislas Wawrinka, Marin Cilic, Dominic Thiem and Dan Evans, who meets Robin Haase in the first round.
In the opposite half, Djokovic begins the defence of his trophy against either Tommy Robredo or Nicolas Almagro, with Kei Nishikori lurking as a potential quarter-final opponent.
The Serbian - who has announced wholesale changes to his coaching team - may also meet Rafael Nadal before the final, with the Spaniard facing either Joao Sousa or Fabio Fognini in the last 32.