Bo Pelini will not return for another season as LSU's defensive coordinator, the school announced.
Pelini, a former head coach at Youngstown State and Nebraska, was brought on to coach LSU's defense in January but ultimately failed to live up to expectations, as the Tigers ranked next-to-last in the SEC in yards allowed per game.
In a statement released by LSU on Monday, Pelini said he and head coach Ed Orgeron "mutually decided it's best'' to part ways.
"I am grateful to call Coach O a friend and I am thankful for the opportunity to come back to LSU, but I have decided to move on in my coaching career,'' Pelini added.
Pelini had two years remaining on his contract. The school said in the statement that the parties agreed to a financial settlement.
More changes are expected to occur on the LSU coaching staff throughout the offseason, a source told ESPN.
LSU failed to recapture the magic of last season, when it went undefeated and won a national championship. The Tigers lost their opening game to Mississippi State and needed back-to-back wins to finish the regular season 5-5.
LSU also allowed 650 total yards in a 55-17 loss to rival Alabama on Dec. 5.
However, the defense showed improvement in four of the last five games, three of which LSU won. The Tigers' defense allowed only one touchdown in a loss at Texas A&M and created six turnovers in a victory over Mississippi last weekend.
"I was proud of how hard our team competed down stretch, the way our young guys stepped up and were developing and the overall direction we were headed,'' Pelini said.
The Associated Press contributed to this report.