Tracy Claeys’ offensive staff might be in major flux, but his defensive staff is nearly set.

The new Gophers football coach filled his only defensive opening Monday by returning longtime administrator Dan O’Brien to his roots.

O’Brien, 52, is a former high school and college coach who had been working at the University of Minnesota as a senior associate athletic director. Considered by some to be a candidate to fill the school’s permanent athletic director job, he instead is headed back to the sidelines after accepting Claeys’ offer to be an assistant coach.

O’Brien will be assistant defensive backs coach, co-special teams coordinator and an assistant to the head coach.

Claeys also confirmed he is leaning toward promoting Jay Sawvel from defensive backs coach to defensive coordinator, with an announcement expected in two weeks.

Sawvel, 44, made the defensive play calls after Claeys moved from defensive coordinator to head coach upon Jerry Kill’s retirement Oct. 28.

“Gosh dang, Jay has been with me a long time, and he’s a heck of a coach,” Claeys said. “We get back [from recruiting] on Dec. 14. We will release everything else with the rest of the staff. There shouldn’t be any surprises to anybody that that’s the way we are leaning.”

Sawvel coached at Eastern Kentucky, Notre Dame and Ferris State before joining Claeys and Kill at Southern Illinois in 2001. Sawvel has been a key recruiter for the Gophers and has helped turn their secondary into a perennial strength, while also serving as special teams coordinator.

O’Brien filled the opening created when the Gophers promoted Claeys from defensive coordinator to head coach after Kill retired for health reasons. O’Brien was the head football coach at Bemidji High School and at Concordia (St. Paul) before becoming a full-time athletic director, first at Concordia and then for six years at Hamline. In 2008, he joined the Gophers as the director of football operations. He moved to a senior associate AD position, helping oversee football, in 2013.

The Winthrop, Minn., native was an All-MIAC defensive back and two-time captain at St. Thomas, where he earned undergraduate and master’s degrees. He was an assistant football coach at Benilde-St. Margaret’s and Lake-ville High School before getting the head coaching job at Bemidji.

Claeys said he tried to hire O’Brien as the team’s linebackers coach in 2013, when Bill Miller left for Florida State, but the timing wasn’t right for O’Brien’s family. The Gophers wound up hiring Mike Sherels.

“Dan’s got a great relationship with the high school coaches,” Claeys said. “He’s from the state of Minnesota, and he and Coach Sherels will recruit here to make sure that we’re giving every Minnesota kid the opportunity.

“And Dan will be my sounding board. He’s been an AD, a head football coach. So I’m excited — all our coaches are — about having Dan and his family join us.”