Sparty's defense is understood by anyone who knows just a little about the X's and O's of football.
I think it's this simple: if Ohio State gets Sparty on a field with calm winds and a dry ball, they can do what Ohio State's offense does. After the lessons learned from the 2013 B1G CG, and what we saw last year, if Sparty gets Ohio St in a situation where the playcallers and/or the QB are not willing/able to throw the ball to exploit what the defense is giving, OR if bad weather limits or grounds Ohio State's passing game, advantage Sparty.
Last fall, the OSU coaching staff chose to try to beat Sparty playing like Sparty (minus the part of giving the ball to the stud RB). Not recommended. But assuming the O braintrust is competent (and I do), then the weather report in E Lansing may be the most important thing about this year's matchup.