When you aren't putting your QBs in constant peril by calling draws, read options, etc. you are much more likely to have a healthy QB because they aren't subject to so much contact. In 2004 Beck missed the Stanford game because he got hurt on a QB run against Notre Dame. That was basically the end of those calls until Riley Nelson became the QB, and since running our QBs more we've seen constant injuries with Riley, Taysom & Zach.