Heigl's rep tells Us: "I am unable to comment."
In February, her costar James Pickens Jr. told Us both Heigl and T.R Knight were leaving the ABC medical drama.
While Knight is off the show, as confirmed to Us by former costar Melissa George yesterday, Heigl negotiated her contract to stay.
Both characters' fates were up in the air on last season's finale. Knight's George O'Malley was hit by a bus, while Heigl, who plays Izzie Stevens, underwent a risky brain surgery to battle cancer.
In the show's final moments, they were both unconscious.