The three key names in that endeavor were quarterback Zach Mettenberger, receiver Jarvis Landry and tailback Jeremy Hill -- all of whom ranked among the nation's most clutch third-down performers. All three are in the NFL now, however, so it will be important for LSU to identify new players capable of keeping drives alive on those all-important downs.
Let's take a look at what could become the key factors in LSU's attempt to remain successful on third down.
Quarterback efficiency, running ability
LSU will have a hard time matching the success on third down of departed quarterback Zach Mettenberger.
The fifth-year senior's 96.7 Total Quarterback Rating on third down trailed only that of Heisman Trophy winner Jameis Winston (96.9) among FBS quarterbacks. Mettenberger was 58-for-89 for 974 yards, nine touchdowns and one interception on third down according to ESPN Stats & Information. Of those 58 completions, 21 went for 20 yards or more -- a total that was second only to Louisville's Teddy Bridgewater (22).
Talented though they may be, a green freshman and a sophomore with one shaky start under his belt are not going to match that kind of passing production. As LSU offensive coordinator Cam Cameron indicated after the Tigers' spring game, they'll have to play it smart early in possessions in order to keep the offense in manageable down-and-distance situations.
Give the young quarterbacks this, though: both of them have an ability that Mettenberger simply does not possess, and it will almost certainly come in handy this fall. Both are good runners, so don't be surprised to see designed runs -- and scrambles after plays break down -- that result in first downs.
Jennings was credited with six rushing attempts on third downs last season, with two of them achieving first downs and another achieving a touchdown. Harris showed off some impressive wheels in LSU's spring game, rushing three times on third down for 45 yards and a touchdown. We'll certainly see more of that in 2014 than when the slow-footed Mettenberger was under center.
Filling Landry's shoes
The question isn't which LSU player replaces Landry's absurd production on third down. It's highly unlikely that one player will do that -- not this fall anyhow -- seeing as how Landry ranked third in the FBS in third-down receptions (28), second in receiving yards (474) and tied for first with six touchdown catches according to ESPN Stats & Information.
2013 FBS Leaders Third-down receptions 35 -- Jace Amaro, Texas Tech
30 -- Justin Hardy, East Carolina
28 -- Jarvis Landry, LSU
27 -- Allen Robinson, Penn State
26 -- Willie Snead, Ball State
Travin Dural caught the game-winning touchdown against Arkansas on third down.
LSU has only one returning wide receiver who was even targeted with a third-down pass last season -- Travin Dural caught 5 of 11 third-down passes where he was the intended target and scored two touchdowns, including the game winner against Arkansas -- so it would make sense for the Tigers to spread around the opportunities more evenly this fall.
Since the receiving corps is loaded with inexperience, a good alternative might be the positions where the Tigers return some experience.
They're extremely deep at tight end, and one of the talking points of LSU's spring practice was about how the position should be more active this season.
Last season, the Tigers targeted the tight end 10 times on third down, but came away with only three completions for 35 yards and one first down. In other words, this will be a two-way street. The tight ends must hold onto the ball consistently if the quarterbacks are to look their way more often.
If LSU's spring game was any indication, the chances will be there. Jennings and Harris targeted tight ends on four of their 12 third-down passes, with DeSean Smith catching two of them for 36 yards and a touchdown.
Likewise, tailback Terrence Magee made it a point this spring that he'd like to catch more balls out of the backfield this fall. The former receiver could be dangerous as a third-down target judging by his three receptions for 46 yards in that role last season.
Fullback Connor Neighbors (one catch on two targets for 4 yards and a first down in 2013) could also become more of a factor in the passing games now that he's taking over for J.C. Copeland in the backfield.
Who handles the backfield workload?
Hill was arguably the nation's most explosive third-down back in 2013, leading the FBS with an average of 13.28 yards per carry on third down according to ESPN Stats & Information. Although dozens of players carried the ball more times on third down than Hill's 18 attempts, he ranked 10th nationally with 239 yards thanks in large part to his touchdown runs of 37, 49 and 69 yards.
Seniors Magee (eight carries, 44 yards, three first downs, one touchdown in 2013) and Kenny Hilliard (eight carries, 36 yards, two first downs, two touchdowns) have handled short-yardage duty well in limited work, but the X-factors might be freshmen Leonard Fournette and Darrel Williams.
ESPN's No. 1 overall prospect for 2014, Fournette has LSU fans drooling over his combination of size, power and breakaway speed. He'll almost certainly play a leading role on third down -- and in every other type of running situation -- early in his college career. And Williams was no slouch himself as a prep star, rushing for 2,201 yards and 32 touchdowns as a senior at John Ehret High School in Marrero, Louisiana.
It's possible that LSU could use all four tailbacks in some capacity, similar to a 2011 backfield that utilized Hilliard, Spencer Ware, Michael Ford and Alfred Blue. Ware led the Tigers with 92 yards on 25 third-down rushing attempts that year, while Blue (16 carries for 85 yards) and Ford (13 carries for 77 yards) led the way with two touchdown runs apiece.
With inexperience at quarterback and receiver and a next-level talent like Fournette joining the backfield, conventional wisdom indicates that LSU will lean heavily on its veteran offensive line and the ground game, especially on third downs. The previously mentioned factors will certainly play an enormous role in LSU's attempt to remain effective on third down, but this might be a season where the rushing attack is the most important element in keeping the chains moving.