re: FB in the slot? WTF?

the concept is simple, you leave 21 personnel (2 back 1 te) in the game and the defense stays in their base 4-3. when you put the fullback in the slot the defense will likely handle it in one of 2 ways: they will either flex an LB, or roll down the SS. If they flex the LB then you may or may not have a good matchup there. What you DO have is the mike having to cover the TE on the stick concept (which is what LSU ran a ton of out of that trey formation). the mike will either be leveraged by staying in his base alignment allowing an easy throw and catch to the TE or slide over (which typically means that backside LB will slide as well creating a 4-2 look) thus creating a favorable look to the single wr side.

if the defense rolls down a SS over the fullback and maintains a 4-3 box then both the fullback and TE are in trouble by alignment BUT what you have created is virtual one on one matchups for the outside wrs because you've dictated a one high safety look. this allows you to check to curls, comebacks, or what ever other one on one routes you want for landry and crew.

bringing in a 3rd wr in place of the fullback is certainly a viable option but will often mean they go to nickel.

as has been said, it is a spring game and last year lsu ran a ton of stick so for opposing teams there's nothing new to see here.