The event's second seed was to face defending champion and fourth-seeded Jelena Jankovic of Serbia.
"I think it was in the beginning of the second set yesterday, I started to feel it," Sharapova told reporters.
On Friday, the Russian needed nearly three hours to beat No. 9 seed Patty Schnyder of Switzerland 6-7 (3-7), 7-5, 6-2 in a quarterfinal match.
Sharapova joined fifth-seeded Serena Williams (back) on the sidelines in the past two days with an injury.
In the 2007 final, Jankovic beat Russian Svetlana Kuznetsova 7-5 6-1.
Sunday's Jankovic-Cornet victor will earn a check for $196,900.