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LSU offensive line coach Jeff Grimes walks off the field with center Will Clapp following a timeout in the win over UT-Chattanooga earlier this season.

LSU expects offensive line coach Jeff Grimes to leave for the offensive coordinator job at BYU, a source confirmed to The Advocate on Wednesday night. first reported the news earlier Wednesday. Grimes will remain with the Tigers through the Citrus Bowl against Notre Dame on Jan. 1, the site reported.

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Grimes, 49, is in his fourth season as the Tigers' offensive line coach. He also served as run-game coordinator.

LSU gave Grimes a significant raise and extension two years ago when BYU approached him about an open position on its staff. The program offered Grimes another contract boost this time around, but the draw of a coordinator role drew him away.

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Grimes spent 2004-06 as BYU's offensive line coach. He was in the final year of a contract that paid him $550,000 per year. Grimes, a Texas native, joined LSU after the 2013 season following a one-year stay at Virginia Tech and a four-year run at Auburn. He is well respected as a line technician and a recruiter. 

His departure comes at a precarious time. The inaugural early signing period begins next Wednesday, and the Tigers have four offensive linemen committed, including the top-ranked junior college tackle in Badara Traore. 

Also, three junior starters on the offensive line — center Will Clapp, guard Garrett Brumfield, tackle Toby Weathersby — are draft-eligible. They all revealed earlier Wednesday that they requested evaluation grades from the NFL Draft Advisory Committee.

Grimes leaves for LSU's season-opening opponent. The Tigers beat the Cougars 27-0 in a game relocated from Houston to New Orleans. BYU fired offensive coordinator and former quarterback Ty Detmer after this season.

Grimes has led something of a resurgence on the offensive line. In a stretch of seven years, from 2007-13, LSU had just two offensive linemen drafted — a startling number that caused a coaching change, many believe. Coach Les Miles replaced Greg Studrawa with Grimes. 

Grimes has overseen a unit that has produced four NFL draft picks in the previous four years, excluding La’el Collins, a surefire first-round selection who dropped out of the draft because of a police investigation that resulted in no charges. 

The Grimes news comes on a day in which LSU lost general manager Austin Thomas to Tennessee, his home state. Thomas left on Wednesday morning, bound for Knoxville, Tennessee. He spent more than four years managing and organizing LSU's recruiting efforts. 

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Sources: LSU general manager Austin Thomas leaving for same position at Tennessee

Follow Ross Dellenger on Twitter, @RossDellenger.