Smith is expected to join Petrino's coaching staff as a defensive assistant coach, according to a report posted on the Web site for WHAS11, a TV station in Louisville, Kent.
Smith moved to Louisville and has been out of coaching since he was fired as Michigan State's coach in 2006 after going 22-26 in four seasons with the Spartans.
It's uncertain what title Smith will have at Arkansas, but Petrino is in need of a secondary coach after Lorenzo Ward resigned Monday to take over as South Carolina's defensive coordinator.
Arkansas associate athletic director Kevin Trainor couldn't confirm Smith's hire on Thursday evening, and Petrino was unavailable for comment. However, Petrino is scheduled to hold a news conference at 1:30 p.m. today to discuss a wide range of topics.
Petrino and Arkansas offensive coordinator Paul Petrino have a familiarity with Smith, who's known as an adventurer who has run with the bulls in Pamplona and climbed Mount Kilimanjaro.
Both of the Petrino brothers worked as assistant coaches for Smith during their climb up the college football ranks.
Bobby Petrino served as Smith's offensive coordinator at Idaho and Utah State before replacing him as Louisville's coach when Smith left for Michigan State in 2003.
Paul Petrino also worked on Smith's staff at several different schools, including serving as his wide receivers coach at Utah State and Louisville.
Smith's name has been mentioned over the past few years for several coaching vacancies, including for the Hawaii job when June Jones left for SMU following the 2007-08 season.
Despite being known for running a wide-open offense, Smith is comfortable on the defensive side of the ball. He served as a defensive coordinator at Nevada, Idaho, Wyoming and Washington State before getting his break as Idaho's coach in 1989.
Petrino Adds His Mentor To His Staff
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