Time of Possession
I think this is a very underrated stat that a lot of people over look when it comes to team defense. Before Tim Tebow took over the starting quarterback position for the Broncos, Denver was averaging about 26 minutes / per game for time of possession. However after the 6 games Tebow has started (from @Miami till @San Diego) the Broncos are now averaging 32 minutes / per game in terms on time of possession. I think this might help why the Bronco defense has suddenly picked. With Tebow at quarterback the Broncos are running the option play allowing a player like McGahee to find more holes in the line. The defense has a lot more time to rest on the sideline thus allowing them to give up fewer yards and play at a higher level overall.
*Note* The top 2 defenses in the NFL right now (Steelers and Texans) are also the top 2 teams for time of possession.
I think this is the biggest reason why the Broncos have been doing so well lately. Tim Tebow does not throw interceptions. This is huge for maintaining control of a game even if the team isn't playing well. Tebow has only thrown 1 interception so far in all six of his games. Contrast that to Kyle Orton who threw 7 interception in five games. Tebow has only thrown for the same amount of touchdowns with a higher yards/completion.
I don't know what it is about certain athletes like Michael Jordan, Kobe Bryant, Tiger Woods, etc but they have it. Definitely Tebow has it as well. Even though the offense has been struggling all night when the team needs a score Tebow always come through in the clutch. It really is uncanny, however I don't think we should be surprised. He did it in high school, he did it in college, and now he's doing it in the NFL.
I think everybody knows that Tim Tebow has to improve his passing if he wants to be a legit starting quarterback in this league. But from I've seen he has been progressing as a passer, his windup throwing the ball is much shorter now for example. However he has a special talent that I don't think should be discarded. I'm not sure if he's going to be a perennial starter in this league but if he improves look out.