The 21-year-old Canadian is scheduled to return in Madrid alongside hitting partner Cyril Saulnier.
This will be the 17-time Grand Slam champion's second tournament since undergoing arthroscopic knee surgery.
The Spaniard will face another French player in the semifinals after third-seeded Paire beat Garcia-Lopez.
The German fired 10 aces and converted 12 of his 18 break opportunities to prevail over the 13th-ranked Belgian.
The Bulgarian defeated sixth-seeded Vesely and the Croat fired 20 aces to overcome fifth seed Granollers.
Who can take advantage of Serena's absence? Breaking down the Madrid Open's women's draw.
There are five events, but this week is the calm before the upcoming clay storm.
Jelena Jankovic and Ana Ivanovic continue to fascinate us after all these years.
Examining Rafael Nadal as his disappointing season winds down.