Former New York Jets running back Curtis Martin is one of the greatest of all time, but that would've been the case even if he had somehow been snubbed his deserved enshrinement in the Hall of Fame.
It's hard to argue against Martin as a top-five running back in NFL history. Not only was he dominant, but he was dominant over the course of his entire career. From a purely statistical perspective, Martin is one of only four backs in NFL history to exceed 14,000 rushing yards in their careers.
The other three backs are Walter Payton, Emmitt Smith and Barry Sanders.
Of those backs, Martin was the only one not drafted in the first round. If that doesn't give you a sense of the hard work he put in to make it into the Hall of Fame, his consistent productivity from the beginning to the end of his career should be evidence to that effect. He tallied over 260 carries in 10 seasons, tied with Walter Payton for second most of all time, and those seasons were all in succession.
Most running backs begin to taper off toward the end of their careers, as age creeps up and wear-and-tear sets in. With that many carries over the years, you'd think Martin would have fallen victim to that fate, as well.
But Martin wasn't most backs and continued to rush for over 1,000 yards per season all the way to age 31. With 1,697 rushing yards in 2004, he became the oldest back in NFL history to lead the league in rushing, at 31 years old.
Along with Sanders, Martin is the only back to post 10 consecutive seasons with over 1,000 yards rushing.
To that effect, he was a top-notch back with two NFL teams; he terrorized defenses as a member of both the Patriots and the Jets. Most of the NFL's best backs were successful with only one team (although, in the case of Barry Sanders, that serves only as further indication to just how great he was). Backs obviously can't control their surroundings, but the fact that he was successful with two teams is further proof of his superiority.
It may have helped that he was brought to New York by the same head coach that helped make him a star in New England, but the rosters were totally different, and plus, he played at a high level long after Bill Parcells had left the team. He excelled regardless of his surroundings.
Not only all of that, but Martin was consistent from beginning to end; he was one of just 11 running backs to exceed 1,400 rushing yards as a rookie, and he became one of just four running backs (along with Payton, Thomas Jones and Tiki Barber) to exceed 1,400 rushing yards at the age of 31.
But he was the only back in NFL history to accomplish both.