KNOXVILLE, Tenn. - There is still one big missing piece to this puzzle that is the LSU quarterback position. And there is one more game in which to fit it in.

No, these No. 1-ranked Tigers aren’t looking past those other Tigers - the 19th-ranked ones from Auburn who come to Tiger Stadium on Saturday - not even with the showdown against second-ranked Alabama looming after next week’s open date.

But make no mistake about it: That epic matchup factors into LSU’s preparation this week, just as it did for the previous three.

Les Miles and his coaching staff have been getting this team more primed each week for that season-defining game. Ever since quarterback Jordan Jefferson was reinstated after four games, the quarterback position has been evolving. Jarrett Lee is the starter, Jefferson is the backup, and the Tigers’ best quarterback is a seamless blending of the two.

LSU’s offense has not been tested by having to play without an effective running game because none of its first seven opponents has been able to put the Tigers in such a predicament even though four of them were ranked when they played LSU.

Neither has the Tigers offense had to come from behind in any significant way. The Tigers trailed Oregon for 6-1/2 minutes during the second quarter of the season opener and they have been even or ahead - mostly ahead - the rest of the time.

If and when LSU finds itself struggling to run the ball effectively, or having to play from behind in a significant way - or both - is when Jefferson’s ability to run - both by design and by necessity against a pass rush - will be most important, perhaps even the key to keeping this steamroller rolling. The Crimson Tide is the team most capable of providing the test that Lee and Jefferson have yet to face.

That is why Jefferson’s snaps and runs have increased progressively each week and figure to do so again this week.

Miles is trying to get Jefferson as game-ready as possible without disrupting what Lee is doing. So far, the coaching staff - not to mention Lee and Jefferson - has done a masterful job of balancing those potentially conflicting goals.

But if the Tigers are going to be operating at optimum efficiency against Alabama, the passing game with Jefferson at the controls has to be game ready as well - big-game ready. The value of Jefferson’s running ability is diminished if the offense becomes one-dimensional when he’s in the game. In three outings he has completed 4-of-7 passes for 69 yards and a TD.

This week is about Auburn, but it’s also about getting Jefferson more heavily involved in the passing game.

This game is LSU’s last hurdle to being undefeated upon arrival in Tuscaloosa.

It’s also the last in-game opportunity for the Tigers to improve their chances of leaving there the same way.