1) MSU must win out
2) Auburn must lose 2 of next 3 (@ARK, @A&M, vs GA), and win Iron bowl
3) Bama must beat LSU
OR
1) MSU must win out
2) Auburn must lose 2 of @ARK, @A&M, vs GA, vs AL
3) Bama must lose 1 of vs UT, vs LSU, @Aub
4) LSU must lose 1 of @Ole Miss, @AL, vs Ark, @UT, vs A&M
It looks like a couple more scenarios could play out, but, one of these is most likely if it were to actually happen.
Then again, "if a frog had wings..."
https://www.youtube.com/watch?v=zMRrNY0pxfM