I believe he wasn't playing because of the protection issues that he may have. Purdue was getting pressure, which forced Golson to flush the pocket for most of the afternoon. Theo provides the leadership and experience necessary to pickup in protection.
Additionally, I think that it is wrong that most people feel that Brian Kelly abandoned the run. The fact of the matter is that Purdue challenged us to throw all evening, and tried to confuse our young quarterback quite a bit. We checked almost every play this evening, because I am certain you won't see too many plays without 8 in the box. This is definitely a positive in my mind because it shows Coach Kelly was taking his time to get Golson in the right look. Ultimately, Purdue was out coached in my mind, which bodes well for the future. Everything Purdue did, was counteracted by Coach Kelly with his checks on the field. This was successful despite the time it took us getting plays in. The fact is that Golson was learning in this game, during live action, and was pretty successful through the air.
Our defense played fairly well throughout the game, even in the secondary. We didn't give up more than 200 yards passing to a team that is pretty predominately favored in that direction. Our coaching staff went into this game knowing that if we limited their passing attack, we would have a good chance. This is why Purdue seemed to be more successful rushing the ball than we were.
In essence, you have two teams that knew what there strengths were and played to them. Purdue is stout against the run, and stacked the box. This resulted in us us predominately throwing the ball, and achieving relatively good success. Conversely, on defense we played the pass, and achieved relative success.
This is how football works! Coaches game plan towards the opponents strength, and the one with the better plan wins. On this day Coach Kelly had a great game plan and ultimately won the game. Lets not try to over think the situation, Purdue is a good team.