Versatility is the key to staying on an NFL roster, especially if you're not a first-round draft pick and have something to prove.
Some players, stuck in one position, find themselves on the outside looking in after an injury limits their effectiveness in their former role, or somebody younger and faster comes along.
The ability to play multiple positions keeps opposing coordinators on their toes, and keeps a player employed.
Here are 10 guys who present multiple threats to the other side.
One of the league's best running backs, he's the all-purpose back every other running back aspires to be.
Jones-Drew can score touchdowns by charging through the lines, or by catching passes.
He is a proven every-down back, as good on third down as he is on the goal line. He can block and return kicks and punts.
He is a defensive coordinator's nightmare.
Devin Hester, like Joshua Cribbs, began impressing the league with his kick return skills, but now has morphed into the Bears' top receiver.
His return ability wasn't as big a part of his game in 2009, but Hester has said he intends to step it up again in 2010.
Michael Vick created new ways of playing quarterback when he was with the Falcons, and he continues to be a thorn in the side of opposing teams.
Vick can take a snap as easily as catching a pass or taking a hand-off,
When Vick is on the field, opposing defenses have to scramble to keep up with what Vick is doing, because the threat could come from anywhere.
Joshua Cribbs does just about everything, and he does it well.
Cribbs runs back punts, kicks, floats, boats, planes, trains, and anything else you can think of.
Besides being one of the league's premier returners, Cribbs can take the snap as a quarterback in the Wildcat formation, run the ball out of the backfield, and line up as a receiver.
He also can defend on punts and kicks, so you never know when this guy is going to hurt your team.
Now that LeQuitter is gone from Cleveland, there is no more popular athlete in the city on the shores of Lake Erie.
You want a pass rusher? I give you DeMarcus Ware.
You want a guy who will completely disrupt your carefully crafted offensive scheme? I give you DeMarcus Ware.
In 80 NFL games, he has recorded 356 tackles, 64.5 sacks, 61 tackles for a loss, 23 forced fumbles, and two fumble recoveries. He also has recorded 18 passes defended and one interception.
Yeah, he's good.
Ronnie Brown is the Dolphin to always keep your eye on when he's on the field.
He can run, catch, block, run the Wildcat, take out the trash, wash windows and do siding. He usually does all that before the end of the first quarter.
Brown will level a guy with a great block on one play, and then streak down the field for a touchdown on the next. His evolving role with the Dolphins makes him an easy guy to put on this list.
Wade Smith just signed a four-year, $12 million deal with the Houston Texans, who now have a guy who can play center and guard.
Smith's ability to play multiple positions on the offensive line gives the Texans an advantage when building their offensive line in 2010.
DeSean Jackson has the kind of athletic ability most people only dream of having.
He can go from zero to sixty in about two seconds, and he is effective from either side of the field. He has the knack for getting in under the coverage and then relying on his explosive speed for the rest.
You can't teach speed, and you can't stop what you can't catch.
When you think Chicago Bears defense, you think Brian Urlacher.
A wrist injury derailed his 2009 season, but that doesn't take anything away from what this guy is capable of.
Urlacher will get in to the backfield and stuff runners, sack quarterbacks, and generally be a menace no matter where the ball is going.
He recovers fumbles and makes interceptions. His speed makes him a threat no matter where he lines up, and his ability to make game-changing plays make him a player to be respected.
David Diehl has started at left tackle for the past three years for the Giants.
He also has started at right tackle and both guard positions in his eight NFL seasons, compiling a string of 112 consecutive starts.
After the 2009 version of the offensive line failed to live up to expectations, Diehl may be moving again, to left guard.
The fact Diehl can play just about any position on the line means that no matter what, he has a job in 2010 protecting Eli Manning.