Candidate Ben Burtnett has decided not to challenge Mayor Bill Falkner.
Burtnett said he broke the news to Falkner on Monday, as he filed the paperwork to withdraw from the race.
Burtnett, a former St. Joseph City Council member, said health problems led to his decision to step away.
"I have problems with my eye and I'm diabetic," he said.
His decision leaves Falkner as the sole candidate on the ballot.
Burtnett said he still has a good relationship with the current council members and enjoys being part of the political process.
"I know all the council members, so I can always express my thoughts to them," he said.
Burtnett offered well wishes to Falkner.
"He is a great guy. I think he has the best interest of St. Joe at heart," added Burtnett.