Wednesday, August 20 2008 -- The fortunes of any NFL franchise can turn on the twist of their lead field general's knee, shoulder, arm or ankle. In other words—any injury can upset a team's chances of making it into the post-season.

Recent injuries to the Minnesota Vikings Tarvaris Jackson and the Cleveland Browns Derek Anderson raise questions for two teams that were considered to be capable of putting up winning numbers.

Jackson suffered a sprained right knee in a preseason game against the Baltimore Ravens. The injury, though not serious, has sidelined the QB until the start of the regular season. For Tarvaris Jackson, this is the fifth time that he's been sidelined by an injury since he entered the league in 2006. That's a lot for anyone, but it is an enormous amount for a young quarterback.

In order to lead in the NFL, QBs must be exceptionally tough and resilient. They have to be in the huddle despite nagging injuries, setting an example through their own play, commitment and behavior.

The injury to Derek Anderson appears to be a mild concussion. Anderson sustained the concussion last week when he was sacked in the second-quarter by New York Giants defensive end Osi Umenyiora. No one has said how much time Anderson will miss, but it's thought that he will certainly be ready for the opener against Dallas on September 7.

The concussion card can be a lethal one in the NFL, knocking players out of the game for long periods, and if they reoccur, ending careers. Anderson does not fall into this category but if he has one, two or three more such injuries, it can affect his confidence and his ability to play.

Of course, most NFL QBs and players carry injuries that are never revealed, simply playing through them until the end of the season. Quarterbacks who do that, such as Brett Favre and Tom Brady, earn the admiration and confidence of their teammates, creating the foundation for true leadership.