Pro football can be a cruel game that is literally perpetuated by its harshness. Consider these circumstances involving the quarterback triumvirate of Vinny Testaverde, Chad Pennington and Byron Leftwich.

· In week three of the 2002 season, Testaverde was injured in a game against the Jaguars and was replaced by Chad Pennington. The following week, Pennington became the Jets' official starting quarterback.

· Last Sunday, Pennington re-injured his right shoulder in the Jets' loss to the Jaguars. On the heels of offseason shoulder reconstruction, it's feared Pennington's future as an NFL starting quarterback may be in doubt. This week, the Jets signed Testaverde to replace Pennington.

· Byron Leftwich, who led the Jaguars to Sunday's overtime victory over the Jets, was Pennington's understudy as a freshman at Marshall, where Leftwich said he got his first true lessons about playing quarterback. Pennington was Leftwich's teacher.

"The guy who taught me the game of football is Chad Pennington. I didn't know anything about coverages or blitzes or anything. I learned all of those things in college," Leftwich said.

Football is full of such twists of fate. It is a fraternity of men helping each other in their attempts to compete against each other. Strange, isn't it?

Here are 10 things the Jaguars have to do to beat the Broncos.

1. Take the game to Plummer—Jake Plummer looked pretty good against the Chiefs, but he remains a hot and cold quarterback who commits grievous errors at critical times. To beat the Broncos, make Plummer beat you.

2. Stop the run—Is this an over-used key to victory? Try winning without stopping the run. The Broncos win with the run.

3. Keep it going, Byron—This is Byron Leftwich's team. He's playing at a high level and his arrow is pointing up. Keep it facing in that direction.

4. Know their strategy—The game plan to beat the Jaguars is obvious: Stop Fred Taylor, force the Jags to pass and then put the heat on Leftwich. Now counter that strategy.

5. Over-achieve up front—The Jaguars offensive line is a sore spot, figuratively and literally. Find a way to play better than expected.

6. Mix run and pass—It's not likely the Broncos will permit Taylor 37 carries; these aren't the Jets. The running downs may have to be passing downs, and vice versa.

7. Do whatever it takes—In this case, given the state of the offensive line, whatever it takes may require the Jaguars to abandon their downfield-passing game and rely more on short stuff that won't require as much pass-protection time.

8. Follow the Seattle script—Denver is a team coming out of a cool, dry climate and off a Monday night game. Fatigue could be a factor, as it probably was for the Seahawks in the second half of the season-opener. So, after halftime, up the tempo.

9. Play low—These are the Broncos, the most notorious cut-blockers in the league. Play low with your pads down, which is a good motto for any game.

10. Feel the enthusiasm—It's building in Jacksonville. Another win would send spirits even higher.