I, too, wondered why Cato did not play against Indiana. He played in the goal line defense against MSU and played very well in that capacity. On Indiana's (I believe it was) first touchdown, Taylor Herbst, was playing in Cato's spot on the goal line defense. If I remember correctly, Indiana scored their first touchdown on about a three yard run in Herbst's direction. Not sure that the play would have had a different outcome if Cato had been in there, but perhaps he would have stuffed it. So, I guess Cato had to have been hurt or suspended (or perhaps he was our secret emergency running back and they didn't want to get him dinged up. LOL)
If anyone knows the story on Cato, I would be interested to hear it.