Carlos Alcaraz is back from injury to try to win a third consecutive Madrid Open this week, with Rafael Nadal also in Monday's draw, but top-ranked Novak Djokovic missing.
Alcaraz will be competing in his first European clay-court event of the season after skipping Monte Carlo and Barcelona because of a right arm injury. The 20-year-old Spaniard begins his title defence against Alexander Shevchenko or Arthur Rinderknech.
Nadal, a record five-time champion in Madrid, continues his comeback from injury by facing American wild-card Darwin Blanch in the first round. The 22-time Grand Slam champion will then meet 10th-seed Alex de Minaur if he advances.
Nadal lost to De Minaur in the second round at the Barcelona Open last week in his first tournament in more than three months.
The 37-year-old Nadal last won the Madrid title in 2017, when he beat Dominic Thiem in the final.
Three-time champion Djokovic will not play for a second consecutive year in Madrid, reducing his clay-court preparations for his French Open title defence.
The 24-time Grand Slam winner is still likely to have the Italian Open in Rome to hone his clay game in mid-May before the event at Roland Garros starts on May 26.
Djokovic is yet to win a title this season after losing in the semi-finals of Monte Carlo. He also skipped the Miami tournament in March.
Top-seeded Jannik Sinner, who beat Djokovic in the Australian Open final, will open his Madrid campaign against Lorenzo Sonego or a qualifier.
Casper Ruud, who won the Barcelona title, faces Zhizhen Zhang or Miomir Kecmanovic in the first round.
Top-ranked Iga Swiatek and defending champion Aryna Sabalenka lead the women's field, with Swiatek looking to win her first title at the clay-court tournament. She will also be out to capture a third consecutive French Open title.
After a first-round bye, Swiatek meets Wang Xiyu or Ana Bogdan. Sabalenka plays Elisabetta Cocciaretto or Magda Linette in the second round.
