MINNEAPOLIS (AP) — Republican U.S. Senate candidate Jason Lewis of Minnesota underwent successful emergency surgery for a severe internal hernia on Monday, just eight days before Election Day, his campaign announced.

The campaign said the condition could have been life-threatening if not treated quickly. An internal hernia is a bulge or protrusion of an organ — often the bowel into the abdomen. It can cause an obstruction or other problems.

But campaign manager Tom Szymanski said in a follow-up statement that his surgery was “successful and minimally invasive. Provided that his recovery continues on a positive trajectory, doctors anticipate that he is likely to be released from the hospital in the next couple of days.”

Szymanski didn’t say when Lewis might resume campaigning.

Lewis, a one-term former congressman best known to Minnesota voters from his days as a conservative talk radio host, is challenging incumbent Democratic U.S. Sen. Tina Smith.

Minnesota Republican state chair Jennifer Carnahan told reporters that Lewis was hospitalized in Hibbing, where Vice President Mike Pence was scheduled to lead a rally Monday afternoon. Szymanski declined to disclose where Lewis was hospitalized, but he confirmed that Lewis had planned to attend Pence’s event.

“Praying for a Successful Surgery and Quick Recovery for our Friend @LewisForMN,” Pence tweeted. “Today. Minnesota and America are with you!”

Lewis experienced severe abdominal pain early Monday morning and was taken to an emergency room, Szymanski said in the first announcement. “Prior to being taken to the operating room, Jason was in good spirits, optimistic, and true to form, he was speculating about when he could resume campaigning, eager to continue fighting for his fellow Minnesotans,” he said.

Smith tweeted well-wishes to Lewis for “a successful surgery and a speedy recovery.”