After less than two turbulent seasons, Auburn fired football coach Bryan Harsin on Monday.
The decision came just before the school named a new athletic director in John Cohen, the former Mississippi State AD.
Harsin's firing also came less than 48 hours after the Tigers lost to Arkansas at home by two touchdowns.
The team dropped to 3-5 and is in danger of missing out on a bowl game for the first time since 2012.
Running backs coach Carnell "Cadillac" Williams will serve as Auburn's interim coach, the school later announced. He's in his fourth season at his alma mater, where he was an All-America selection at running back and set team records for carries (741) and rushing touchdowns (45). Williams was selected at No. 5 overall by Tampa Bay in the 2005 NFL draft, and played seven NFL seasons, rushing for 4,047 yards and 21 touchdowns.
Harsin's tenure at Auburn ends with a 9-12 record.
"Auburn University has decided to make a change in the leadership of the Auburn University football program," the school said in a statement. "President [Christopher] Roberts made the decision after a thorough review and evaluation of all aspects of the football program. Auburn will begin an immediate search for a coach that will return the Auburn program to a place where it is consistently competing at the highest levels and representing the winning tradition that is Auburn football."
Per terms of his contract, Harsin will be owed $15.5 million in buyout money with 50% due within 30 days and the remaining half in four installments.
Two years ago, the school decided to pay a $21.7 million buyout to fire Gus Malzahn, who had gone 68-34 in eight seasons.
"I am incredibly disappointed that I won't get to lead the Auburn football program and these players into the future," Harsin said in a statement released Tuesday. "I poured my heart and soul into this program and team. We stood together in the face of considerable challenges and outside noise.
"Through my entire time at Auburn we did things the right way, which is not always the easy way. I am very proud of the resolve shown by everyone in our facility and incredibly grateful for those at Auburn who stood by me and my family. I am certain that this group of players will do great things. I will miss you guys tremendously but will always be there for you and do anything I can to help moving forward. Thank you for believing in me."
Auburn was coming off a 6-7 season when Harsin's status was thrown into limbo this February after the university launched an investigation into his handling of the program.
The inquiry came after a number of players and coaches left during the offseason.
Auburn ultimately cleared Harsin, who later called it a "personal attack" that "didn't work."
"Like any coach with the benefit of hindsight, there are things that could have been done differently," added Harsin. "I don't pretend to be perfect but I am certain I will be better moving forward because of this experience.
"I truly believe Auburn has the potential to be a championship program once again. The resources, financial support and fan base are in place. There are good people throughout this program and University. With complete alignment, the possibilities are endless."
Auburn opened the season with two straight wins, over Mercer and San Jose State, but has gone 1-5 since.
Harsin, 45, came to Auburn on a six-year, $31.5 million deal after seven seasons as head coach at Boise State.
His record as a head coach, including one season at Arkansas State, is 85-36.