A day after news came out about Sen. John McCain’s, R-Ariz., brain cancer diagnosis, his one-time political opponent urged the ailing senator to think about his political future sooner rather than later – and expressed interest in the possibility of her taking over his Senate seat.

“I hope Sen. McCain is going to look long and hard at this, that his family and his advisers are going to look at this, and they’re going to advise him to step away as quickly as possible, so that the business of the country and the business of Arizona being represented at the federal level can move forward,” Kelli Ward, who lost to McCain in last year’s Republican primary and is now running to unseat Sen. Jeff Flake, R-Ariz., told an Indiana radio station Thursday.

In a statement posted later on her website, Ward said McCain’s cancer is “both devastating and debilitating” and he “owes it to the people of Arizona to step aside” when he’s no longer able to perform his duties.

McCain’s office announced Wednesday that he’d been diagnosed with glioblastoma, an aggressive type of brain cancer. The diagnosis, which followed a surgery to remove a blood clot above the left eye, raised questions about when and if he will go back to the Senate.

McCain isn’t up for reelection until 2022. He also had not indicated that he will relinquish his seat, even assuring in a recent tweet that he’ll be “back soon.”

Still, the possibility of him leaving was raised in Ward’s interview. Host Pat Miller asked Ward, a physician and a former Arizona state senator, about whether she believes McCain can resume work.

“I would never presume to say what someone’s prognosis is without having examined them. As a Christian, I know there can always be miracles. But the likelihood that John McCain is going to be able to come back to the Senate and be at full force for the people of our state and the people of the United States is low,” said Ward.