More details emerged Tuesday morning about a pair of LSU defensive linemen who sustained injuries on Sunday.

Defensive end Christian LaCouture and outside linebacker/end Isaiah Washington have been ruled out for the season, a source confirmed to The Advocate.

LaCouture, a senior, tore the anterior cruciate ligament in his knee during a non-contact drill Sunday, and Washington, a sophomore, suffered serious ligament damage as well.

LaCouture’s highly anticipated senior season ended before it even began, and it throws the Tigers' defensive line into unexpected shuffling mode a month before the season opener. LaCouture, a 300-pounder who spurned the NFL to return for his senior year, was expected to play a key role in new defensive coordinator Dave Aranda's 3-4 scheme.

He was LSU’s presumed starter at defensive end, a versatile lineman who played nose tackle as well and, at times, slid inside to a tackle spot. LaCouture is a true senior, meaning he has not used a redshirt year. The NCAA gives players five years to play four seasons. Conceivably, LaCouture, who graduated last week, could use his redshirt year this season and return as a fifth-year senior next year.

The blow of his loss may, somewhat, be absorbed by the potential return of 340-pound Travonte Valentine, the No. 1 junior college tackle in the nation in this recruiting class.

Valentine, dismissed from LSU last summer, told 247Sport.com that he’s been cleared to rejoin his old team. An LSU spokesman could not confirm that news Tuesday, but Valentine has been admitted to school, a source confirmed. LaCouture’s backup at end is Frank Herron, a fourth-year junior who played in a reserve, rotating role last season.

But LSU could move nose tackle Davon Godchaux, originally an end, back to the outside and replace him at nose tackle with a variety of players, including Valentine. The door is also open for new guys like Rashard Lawrence and Ed Alexander, highly touted big bodies who might now see significant playing time.

Washington backed up Arden Key at the Buck position, a hybrid defensive end/outside linebacker spot. Tashawn Bower, working at both the Buck and F-linebacker, is presumably behind Key. Freshmen Sci Martin and Ray Thornton are the only other two known to be working at Buck.

Both LaCouture and Washington are no stranger to injuries. LaCouture broke his forearm in the Tigers' bowl game against Texas Tech in December. Washington missed the first three games last season after breaking his hand in preseason camp last August.