By Vidur Malik

The shelf life for an NFL running back is usually short, and when the prime years have passed, it happens abruptly. Running backs can go from putting up a string of 1,000+ yard, 10 touchdown+ seasons, to being demoted to a third-down or situational back in the matter of a season or two.

The Washington Redskins currently have three backs who could fall into this category. Larry Johnson, Willie Parker, and Clinton Portis have all been considered elite running backs at one time in their careers, but have since dropped from that level. Here’s a look at all three Redskin backs, and how they could fare this year:

Clinton Portis-

Portis looks to be the starter coming into this season, and is not far removed from his 1,000 yard years. He only put up 494 yards and one touchdown last year, but missed half the season because of a concussion. Only two years ago, Portis had 1,487 yards and nine touchdowns, so his elite number days are probably not behind him. One good sign is that his yards per carry average has usually stayed around the 4.0 mark recently. One of the signs of an aging running back is a significant drop in yards per carry, and even though Portis is far from the impressive 5.5 yards per carry he had his first two seasons, he has still been solid in that category. He did take a few dips into the 3.8-3.9 mark a few years ago, but if he can keep it to around 4 this year, that should result in a productive season. He should be able to approach the 1,000 yard mark if he has been able to shake off the concussion, and if he can stay healthy, Portis should be a back you can draft pretty confidently.

Larry Johnson-

Johnson is not the back he once was. After putting up back-to-back 1,700+ yard seasons in 2005 and 2006, Johnson has not been able to get past a foot injury, which has sidelined him for games, and made his numbers take a severe drop. Last year, with the Cincinnati Bengals, he recorded only 204 yards with 0 touchdowns, while Cedric Benson resurrected his career with an All-Pro season. It doesn’t look like Johnson will be able to do the same in Washington. He’ll have to beat out Portis, or at least compete with him to get significant playing time, and with new quarterback Donovan McNabb and a solid group of receivers on offense, it will be tough for Johnson to get many reps. It’s sad to see a guy who was once the class of running backs struggle to get carries, but the situation isn’t ideal for Johnson, and unless you’ve got a late pick that you don’t know what to do with, it might be smart to hold off on him.

Willie Parker-

It looks like the man they used to call “Fast” Willie Parker will need to find a new nickname. Parker’s drop in production may be the most difficult to reverse of all three Redskin backs. While Portis and Johnson haven’t performed as well as they used to, it isn’t as difficult for them to show flashes of their former selves, because they are both downhill runners who make one cut and use their vision to explode through holes. Parker only relied on his quickness to gain yards in his glory days as a Pittsburgh Steeler, and when the speed goes, a running back’s time on the top is usually gone as well. After three consecutive 1,200+ yard years, Parker suffered a toe injury in 2008, which was the beginning of the end for him. He only had 98 carries last year, and didn’t score any touchdowns. Reports indicated that Parker lacked speed at the Redskins’ minicamp, which means that he isn’t a guy worth drafting.