Republican candidate for governor Jeff Johnson on Monday underwent unexpected surgery for a perforation in his stomach.

According to his campaign and staff at Hennepin County, where he is a commissioner, Johnson had stomach pain on Monday morning and went to urgent care. Shortly thereafter doctors decided he would need immediate surgery and he was moved to Maple Grove Hospital.

During surgery, doctors found what his campaign said was a "small perforation in Jeff's stomach. The perforation was repaired." By Monday afternoon, Johnson was out of surgery and recovering.

"Commissioner Johnson is in the Maple Grove Hospital and is expected to be there for about a week," according to an email from Hennepin County's director of public affairs Carolyn Marinan.

Gregg Peppin of the Johnson campaign said that Johnson had not previously had stomach problems.

The campaign cleared Johnson schedule for the rest of Monday and is expected to clear it for Tuesday. Peppin said the rest of the schedule is unclear.

He will have little time to recover before facing four-way Republican gubernatorial primary next month. On Aug, 12, he will vie against former House Speaker Kurt Zellers, former House Minority Leader Marty Seifert and businessman Scott Honour.

Over the weekend, Johnson was on the campaign trail and tweeting about his activities.

Johnson's primary opponents wished him their best:

Gov. Mark Dayton began a Monday afternoon conference by wishing Johnson his best.

"I hope that he has a speedy and complete recovery," Dayton said.

Johnson is not the only Minnesota candidate to have election year surgery.

DFL Gov. Mark Dayton had hip surgery earlier this year to repair a detached tendon in his hip, one of three Mayo Clinic procedures he has had done since taking office four years ago. Back in 2006, when she was making her first run for office, Democratic U.S. Sen. Amy Klobuchar had two hip surgeries.

Updated