Who should i start for my flex spot?

I'd go with Garcon, Bush and Mathews are risky starts as both are involved in RB committees. Although Bush looked good last week, it's clear McFadden was the even better back, it's tough for a #2 RB to have consistently good numbers each week, so I'd eliminate Bush. Mathews has simply been a disappointment all year long, each week, some so-called expert comes along and says this is the week Mathews breaks out, well I'd just wait until we actually see something. For now, he's got a major roadblock in Mike Tolbert. Garcon should offer solid production this week, just like last as the 2nd best receiving option in Peyton Manning's arsenal.