"My health hasn't been good and some of my friends have said that I need to take care of those issues," Peterson said, adding that he fully supports Republican Ralph Okerlund, one of four candidates now vying for his seat.
"I've always firmly believed there's so many good people out there that can do this job," he said. "If anyone ever stepped up that was credible and willing and didn't have an agenda, I'd step aside."
The 41-year-old rancher and farmer, a son of former Utah Agriculture Commissioner Cary Peterson, was appointed to the Senate in 2005 after serving two House terms and was elected in 2006. He described his Capitol Hill voting record as "fairly conservative."
During the recent legislative session, Peterson sided with Sen. Margaret Dayton, R-Orem, to vote down a bill to fund the state's International Baccalaureate education program.
He later investigated the program firsthand and changed his position to one of support.
Senate District 24 attracted many candidates by Monday's filing deadline. Besides Okerlund, Republican Eddie Cox from Fairview, Benton Peterson, a Constitution Party candidate from Manti, and Democrat Tobiah Dillon from East Tooele, jumped in.
Okerlund, currently a Sevier County Commissioner, also served on the Monroe Town Council and as mayor.
"I think he's a fine man. This is a guy who's clearly capable of doing the job," said Peterson.
Recent high-ranking positions with the Utah Association of Counties and the State Association of County Commissioners have left him well-connected on Capitol Hill, said the 55-year-old Okerlund.
"This seems to be a natural progression. I've been contacted by some folks who thought I'd be good," Okerlund said.
"I talked to Darin about running and told him I didn't want to run against him - but he's been thinking about not running for awhile."
Another current legislator, Rep. LaWanna Shurtliff, D-Ogden, is bowing out after 10 years in the House.
The retired school teacher and public education advocate, could not be reached for comment Monday and Tuesday.
Democrat Ed Allen, a former state senator, has filed for the House District 10 slot, along with Republican Brent Wallis.
