Grace, Schmidt, Moore, Morgan (first half suspension?). I would agree when combined with the defensive losses in the middle including starting your fifth string Mike linebacker and missing your starting defensive tackles. Then having backups go down and bringing one guy essentially out of retirement to put his hand in the dirt at Troy.
The only caveat is that the season was lost before USC after not kicking the PAT against NW and blowing the 'Ville game. But a win against SC might have healed some wounds.