Republican candidate for governor Jeff Johnson on Monday underwent unexpected surgery to repair a perforated stomach.

According to his campaign and staff at Hennepin County, where he is a commissioner, Johnson had stomach pain Monday morning and went to urgent care. Doctors soon decided Johnson needed 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." Campaign officials said that it was repaired and that Johnson was out of surgery by Monday afternoon and recovering.

Hennepin County Director of Public Affairs Carolyn Marinan said in an e-mail that "Commissioner Johnson is in the Maple Grove Hospital and is expected to be there for about a week."

Gregg Peppin, of the Johnson campaign, said Johnson had no previous history of stomach problems.

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

Johnson is locked in a four-way battle for the Republican gubernatorial primary on Aug. 12, and his recovery time will eat into those remaining weeks.

He is vying against former House Speaker Kurt Zellers, former House Minority Leader Marty Seifert and businessman Scott Honour, all of whom immediately took to Twitter to offer their wishes for his recovery.

Gov. Mark Dayton began a Monday afternoon news conference by wishing Johnson "a speedy and complete recovery."

Johnson is not the only Minnesota candidate to have the misfortune of having surgery in an election year. Dayton had hip surgery this year to repair a detached tendon — one of three Mayo Clinic procedures he has undergone since taking office four years ago. In 2006, when she was making her first run for office, Democratic U.S. Sen. Amy Klobuchar had two hip surgeries.

Rachel E. Stassen-Berger • 651-925-5046