Top seed Naomi Osaka edged past Greece's Maria Sakkari 6-1 4-6 6-3 in round one of the Birmingham Classic.
Karolina Pliskova and Johanna Konta were victorious at the Birmingham Classic, but Elina Svitolina suffered a first-round exit.
Preparing a challenge for a sixth Wimbledon title, Venus Williams will play the Nature Valley Classic for the first time.
Johanna Konta has impressed on clay this season but was unable to stop Karolina Pliskova triumphing at the Internazionali d'Italia.
Johanna Konta celebrated her 28th birthday by reaching the semi-finals of the Internazionali d'Italia in Rome on Friday.
Despite locking up the top seed for the French Open, injuries have affected Naomi Osaka in the build-up to Roland Garros.
A right hand injury forced world number one Naomi Osaka to withdraw from the Internazionali d'Italia on Friday.
While Simona Halep insisted fitness was not an issue ahead of the French Open, Naomi Osaka eased through at the Internazionale d'Italia.
Simona Halep's early exit in Rome ensured Naomi Osaka has achieved her goal of being top seed at the French Open.
Former world number one Caroline Wozniacki was unable to complete a first-round match for the second successive week due to a new injury.