Just like their D.
Against Baylor and Oregon, they put up 366 yards, averaging 5.0 and 5.6 yards per play respectively. They could not run the ball against either team, averaging 2.5 yards per carry in each game. They moved the ball well against USF and Wyoming, putting up over 500 yards, and averaging 8.3 yards per play in both of those games, running for 8.4 and 6.3 yards per carry respectively.
Utah State was a bit of a mixed bag. 397 yards, 6.6 ypp, rushing for 3.7 yards per carry. It was really a tale of two halves though. In the first half, BYU's drive chart went TD, Punt, Punt, Punt, FG, Half (20 plays, 107 yards). Excluding sacks, they had -11 rushing yards. In the second it went TD, TD, Missed FG (33), TD, Downs, Missed FG (35), Game (43 plays, 290 yards). 23 for 141 on the ground.
The game is a nice post-bye-week test of whether the improvements we saw in the second half against Cal and all game against UNC were a true trend and here to stay. BYU isn't bad, they're not loaded up on one side of the ball or the other... they're a decent, balanced, borderline top 25 team. If we've improved like we think we have, we should beat them by two scores. If we're not able to win this one, we're in for a long season.
In short, I think the outcome of this game is going to be determined much more by how well our lines are able to play rather than by anything BYU does.