Smith was on the verge of having a long, prolific career, but he chose to walk away to study medicine. He retired as the Minnesota Vikings' all-time leading rusher. He's since been eclipsed by some dude named Peterson or something. (AP Photo/David Stluka)

Dillon toiled for years with the Cincinnati Bengals, but finally got his chance to shine with the New England Patriots at the end of his career where he finally got a ring. (AP Photo/Darron Cummings)

He gets covered up a little bit because he split time with Warrick Dunn, but Alstott was able to do it all for the Tampa Bay Buccaneers. He was a six-time Pro Bowl selection. (AP Photo/David Drapkin)

The aforementioned Dunn lost a lot of touchdown runs to Alstott. But he's currently 19th all time in rushing yardage. (AP Photo/Chuck Burton)

Unfairly remembered for "The Fumble," which hurt the Cleveland Browns' chances for a Super Bowl bid. But he was one of the most productive backs of his era. (National Football League)

Green was a four-time Pro Bowl running back for the Green Bay Packers and led the NFC in rushing in 2003.(AP Photo/Steve Nesius)

Brooks was a four-time Pro Bowl selection for the Cincinnati Bengals. Brooks excelled at running, receiving and kickoff returns. (AP Photo/Al Golub)

The "Nigerian Nightmare" emerged from obscure NAIA Azusa Pacific and became a force for the Kansas City Chiefs for a number of seasons. People talk about Bo Jackson on "Tecmo Super Bowl", but Okoye is no slouch in that game, either. (AP Photo/Chris O'Meara)

Dupree was injured for most of his pro career, the majority of which was wasted in the USFL. Dupree did give it a go with the Los Angeles Rams, but he just couldn't make it happen. But to hear greats like Barry Sanders tell it, Dupree might have been the best running back to come out of Oklahoma. (AP Photo/Joe Giron)

Perkins was one of the first offensive superstars of the Dallas Cowboys. In fact, he was the first Cowboys player to be selected to the All-Pro list (1962). (National Football League)

Before there was Kurt Warner, Curt was a pretty fair running back for the Seattle Seahawks. Warner was selected to three Pro Bowls during the 1980s, and rushed for 1,449 yards with 13 touchdowns as a rookie. (National Football League)

The Seahawks had another awesome running back who followed Warner. Warren also went to three Pro Bowls, but was often overshadowed by some of the great running backs of the 1990s like Emmitt Smith and Barry Sanders. (AP Photo/Al Golub)

You think of the great "Air Coryell" offenses in the late 1970s and early 1980s, you often forget Muncie was a huge part of the ground attack. Muncie tied the single-season record with 19 touchdowns in 1981. (National Football League)

You might not believe this, but the New York Jets were actually good in the 1980s. (Seriously, Google it.) McNeil was the stud running back for the team who made quarterback Richard Todd look good. (AP Photo/Paul Spinelli)

Andrews went to four consecutive Pro Bowls for the Atlanta Falcons from 1980-83. But a serious knee injury derailed a potential Hall of Fame career. Andrews rushed for a career-high 1,567 yards in 1983 before his injury. (National Football League)

Foreman was a perfect runner for those frigid days at the Met in Minneapolis. But he's not given enough credit for being a great receiver out of the backfield. He led the league with 73 receptions in 1975. (AP Photo/PKS)

One of the big backs who burned out a little bit too quickly. A true workhorse who carried the ball 403 times in 2000 for the Tennessee Titans. He was never the same after that. (AP Photo/Mark Humphrey)

Pittsburgh Steelers fans will whine until Bettis gets into the Pro Football Hall of Fame. But did you realize he averaged less than four yards per carry? Nobody considers him the best of his generation. If you want to recognize him for being a guy who hung around longer than most big backs, fine. That doesn't get you in the Hall of Fame. (AP Photo/Keith Srakocic)

Cribbs was a dominating running back who followed in the footsteps of O.J. Simpson in Buffalo. If he didn't detour into the USFL, it's not hard to imagine him in Canton. (AP Photo/Al Golub)

The H-Bomb was one of the most prolific running backs in pro football history. But again, his USFL career takes away from his Pro Football Hall of Fame credentials. Even though, you know, the USFL was pro football. (AP Photo/Duncan Livingston)

Watters was the perfect fit for the San Francisco 49ers offense; a guy who had the ability to run the ball and catch it out of the backfield. You have to wonder if his prickly personality is what is keeping him out of the Pro Football Hall of Fame. Oh wait, you don't have to wonder at all. (AP Photo/Ed Reinke)

I don't get this one. Anderson was a true stud in every sense of the word. If his early years weren't languished in the football graveyard of St. Louis, he would no doubt be in the Pro Football Hall of Fame. He was a better receiver than he is given credit for and he was the MVP of Super Bowl XXV. (AP Photo/Al Golub)

Do yourself a favor and Google this guy. I only remember him from NFL Films footage because he's another great running back whose career was cut short by injuries. When Barry Sanders arrived in Detroit, then-coach Wayne Fontes wanted him to wear No. 20 in homage to Sims. (National Football League)

Craig was a huge part of the San Francisco 49ers' success during the 1980s. In 1985, he became the first running back in NFL history to top 1,000 yards in both receiving and rushing. His absence from the Pro Football Hall of Fame might be most egregious when you look at the length of his career and the impact he had on one of the greatest teams of all time. (AP Photo/Greg Trott)

Davis' bid for the Pro Football Hall of Fame is hurt because his career ended so abruptly. But for my money, I'd rather celebrate a guy who had a huge impact and was the best at his position instead of a guy who was all right for a number of years (looking at you, Bettis). He averaged better than 4.5 yards per carry during his peak years. Do the right thing already and put him in the Hall of Fame. (AP Photo/Kevin Terrell)

That's right, Bo Jackson is the greatest running back not in the Hall of Fame. You saw the ESPN doc on him, so you can't deny this. Nobody could stop him on the football field. His cultural impact is through the roof. And he absolutely quantifies the whole "you can't tell the story of the NFL without this player" requirement. And really, if Jackson was selected to the Pro Football Hall of Fame would anybody question it? Of course not. So, uh, can we put him in? (AP Photo/Beth Keiser)