Biggest X-Factors for Steelers vs. Broncos AFC Divisional-Round Showdown

There are a ton of question marks in Sunday's divisional-round showdown between the Pittsburgh Steelers and Denver Broncos, leaving the game ripe for X-factors to take over.

Who is the biggest X-factor in the matchup? Which player in the Broncos secondary will be the most pivotal against a hobbled Ben Roethlisberger?

Watch Adam Lefkoe and Bleacher Report NFL Analyst Chris Simms reveal their X-factors in the video above.