The career of an NFL player can be a long and twisting road. There are no formulas for success and no tangible formulas for failure. However, every season, certain players have to know that if they don't perform that year, their future earning potential could be seriously hampered to the point where they are either out of the league altogether or they must begin to view themselves as "journeymen" who will never sign that elusive enormous free agent contract that sets them up financially for life.

We've identified five such players whose situations will be most interesting in 2006. Surely there are more than five players in the NFL who must perform this season in order for their high earning potential to remain a real possibility, but we feel that these five present the most intriguing situations.

1. J.P. Losman

It seems awfully early for this year to be Losman's make-or-break season, but the young QB is facing the possibility of being traded, released or being relegated to a long-term backup role if he doesn't show improvement early in the 2006 season. The Bills gave up a lot to earn the right to draft Losman in 2004, and the team jettisoned established starter Drew Bledsoe last year to give Losman the opportunity to start. Losman struggled mightily, and was replaced by Kelly Holcomb. This offseason, the Bills signed Craig Nall from the Packers and currently have Holcomb listed at the top of the depth chart. Losman needs to grab hold of the job immediately and hold onto it, lest he be cast to the scrap heap.

2. Chad Pennington

Pennington was seen not long ago as the possible "next Joe Montana" given the similarities in style, statistics and leadership he appeared to have in common with the 49ers' legend. However, his throwing shoulder was shredded twice, and his ability to stay healthy and viable in the long-term is in serious doubt. The Jets have a new coaching staff and have no prior commitment to Pennington, who needs to show that he is healthy and can be durable in order for him to stick with the Jets. If not, the team will almost assuredly look in a different direction for a QB.

3. Aaron Brooks

Brooks took the league by storm in 2000 when he lead the New Orleans Saints to the playoffs, and his career seemed destined for certain stardom at that time. Since then, his long-term outlook, as well as his play, has regressed dramatically. The Saints let him go after last season, and he was signed by the Raiders. The Saints replaced Brooks with Drew Brees, another QB with shoulder questions, and Brooks must perform with the Raiders in order to prevent his new team from turning to a young and promising QB currently sitting behind Brooks on the depth chart, Andrew Walter.

4. Jamal Lewis

Lewis was one of the most feared RBs in the NFL as recently as 2003, when he rushed for an astounding 2,066 yards. His career has taken a turn for the worse since then as a result of injuries, legal problems and a baffling decline in production. Lewis was a free agent after the 2005 season, but after getting no big-time offers, returned to the Ravens with a relatively modest one-year contract. Although Lewis doesn't turn 27 until August, he has taken a beating in the NFL and must show that he can still carry the load if he's to get a big payday in 2007.

5. Charles Rogers

Rogers was the second overall pick in the 2003 draft by the Detroit Lions, and he came into the league with enormous expectations. Since then he has done nothing but disappoint his team and their fans. Rogers has been hurt repeatedly, and played in only six games in his first two seasons. Not only has his health been questioned, as he broke his clavicle several times, but his work ethic has also been assailed by various officials associated with the team. The Lions have many other WRs on the roster who came into the league with the same expectations, and if Rogers doesn't show something immediately, he may not even make it to training camp.

Over the course of history in the NFL, many players face the same situation in a given year as the five mentioned above. Some have seen the writing on the wall and excelled, and others have faded into the sunset. History also tells us that some of the players listed here will go on to successful careers and others will not. What is certain is that each of these situations bears watching in the coming weeks and months.