The Denver Broncos gave Peyton Manning a 5-year, $96 million deal, but they also made sure that they protected themselves should Manning under-perform or suffer another injury. According to Pro Football Talk's Joe Florio, here are the details:
... if Manning is on the Broncos’ roster on the final day of the 2012 league year, his base salaries of $20 million in 2013 and $20 million in 2014 become fully guaranteed.
In other words, the Broncos can cut Manning at any point after Super Bowl XLVII and before the last day before the start of the 2013 league year and limit the contract to a one-year, $18 million investment. And so, just as the Colts faced a $28 million decision in March 2012, the Broncos will face a $40 million decision in March of 2013.
The Broncos are on the hook for $18 million in 2012, but if Peyton Manning proves worse than expected, the team can cut him before the start of the 2013 league year (March 2013), which nullifies the rest of the contract. The Broncos again have options to cut bait after the 2014 and 2015 seasons, and those are outlined by Florio as well.