For LSU football, a charmed offseason has finally run out of rainbows.

First, the gloom Tuesday, as the school announced defensive end Christian LaCouture and end/outside linebacker Isaiah Washington will miss the entire season with knee injuries. LaCouture, the senior, tore an ACL Sunday in a noncontact drill. Washington, a sophomore, suffered a ligament tear as well.

Their loss did much to overshadow what was, if not 100 percent good news for LSU, something quite encouraging and, now, desperately needed. Travonte Valentine, LSU’s on again/off again, oft-troubled defensive lineman, has been cleared to practice and enroll in school but won’t be declared eligible to play unless he can pass a summer intersession course.

Two hammer blows of bad news and one probable but not certain piece of good news add up to a net loss for the Tigers, who must now rescramble the egg of new defensive coordinator Dave Aranda’s 3-4 defense.

Aranda’s scheme contains so many mirrors and sleight of hand tricks that had LSU not announced it, no one may have known LaCouture wasn’t out there until the second quarter of the Wisconsin opener. But the void is there, one that Valentine must help fill.

In Valentine, LSU has an imperfect but now even more precious substitute. He will be called on to play even more snaps and take an even bigger role with LaCouture gone than he was before — maybe even doubling his snaps from something in the teens to somewhere in the 30s per game. All the while, Les Miles will be praying for the sake of this crucial season in his 12-year LSU tenure that Valentine doesn't slip off the straight and narrow somewhere, that he has grown up, that he doesn't get injured, too.

But back to LaCouture. You don’t have to be an LSU fan to have compassion for the senior from Lincoln, Nebraska, who passed up a chance to leave early for the NFL to return to LSU and try to help led the Tigers back to the national summit.

“Anything less than a national championship is going to be unacceptable,” LaCouture said the day he and five teammates announced they wouldn’t leave early for the NFL but return for their senior seasons. “We have to work toward it, of course, but all the pieces are in place.

“We should have a special year.”

LaCouture put in the work all right, first recovering from a broken arm he suffered in LSU’s Texas Bowl victory over Texas Tech. He spent his summer boxing to improve his coordination and physique, shedding 12 pounds to reach a more sculpted 300-pound playing weight.

Now, what does the future hold for him? Does he turn pro after this season, knowing full well NFL clubs will discount his heart, his desire, coldly judging him as damaged goods, affecting his draft stock? Does he instead prove himself through the agony of rehab, the sweat, the grinding work, to try all over again as a fifth-year senior in 2017?

Right now, these are probably questions not even LaCouture can answer with any certainty. The only thing certain is the choice is his to make. He’s more than earned the right.

As for Valentine, for LSU fans there may be a distant echo to his playing situation in that of two key former Tigers defensive linemen.

LSU had to recruit and re-recruit Chad Lavalais before he became a fixture on the Tigers’ 2003 BCS national championship team. He may well have made the most crucial play that season, shoving Ole Miss left guard Doug Buckles into Rebels quarterback Eli Manning on a late fourth down play, preserving LSU’s tense 17-14 victory in Oxford that kept the Tigers on track to the Sugar Bowl.

In 2007, Rickey Jean Francois was lost to academic ineligibility most of the season. He only played in the SEC Championship Game against Tennessee and in the BCS National Championship Game against Ohio State, taking a personal wrecking ball to the Buckeyes’ offense and blocked a field goal en route to earning defensive MVP honors.

If Valentine can have half the impact Lavalais and Jean Francois had on those seasons, LSU’s investment in bringing him back and getting him eligible may be worth it. But it probably won’t eclipse what LaCouture’s play and leadership could have meant to the Tigers. It will take a collective effort across LSU’s defensive front, far beyond what Valentine alone can give, to do that.

Follow Scott Rabalais on Twitter, @RabalaisAdv.​