The View alum, who underwent a mysterious surgery in October, explained at the top of the show: "I had a tumor in my abdomen."
"The doctor said, 'You got to get it out by the end of the month, we don't like how it looks'," she continued. "I had a scary week when we didn't know what the result were. But I'm OK... everything came back OK. Surgery's not fun, but it is necessary to find out if you have something really terrible."
Though it was "a bit of a scare," Hasselbeck added that she had the "blessing of it not being cancer."
"So many people I know have stared down the barrel of that cancer gun, and looked at it when they have gotten bad news... and done remarkable things, courageously to fight it," Hasselbeck said. "So I knew if I got that kind of news I would be in their wings and, by their example, able to fight it. I didn't get that message from my doctors. I got a clear and clean bill of health and I'm thankful."
Watch Hasselbeck explain her absence below: