LSU will be without defensive line coach Jimmy Lindsey when it opens preseason camp on Thursday.
Tigers coach Brian Kelly announced on Wednesday that Lindsey is stepping away from the team to deal with a "personal health matter."
Assistant John Jancek will shift to defensive line coach.
Bob Diaco, a senior defensive analyst, steps into Jancek's vacated role as special teams coordinator and linebackers coach.
"Our prayers are with Coach Lindsey and his family, and we ask that their privacy be respected," Kelly said in a statement. "We look forward to his return to the program."
Diaco, who was the head coach at UConn from 2014 to 2016, was most recently the New Jersey Generals defensive line coach in the USFL.
LSU won 10 games and the SEC West during Kelly's first season in Baton Rouge.
The Tigers open the season against Florida State in Orlando on Sept. 3.