Sorry, without a doubt Manning was showing some dents in his armor last season - from here on in it's all down hill. And without Manning playing like an All-Pro, The Colts are an 8 win team at best. Without Manning at all, The Colts are a 4 win team at best.
The Colts' OL was god awful last year and half the team was injured, yet they still won 10 games. All those dents in Manning's armor go away if the OL plays at least average.
Without Manning yes, the Colts are a 4 win team. But Manning is one of the most durable QBs to ever play the game, so that doesn't' worry me.