Undrafted NFL Free Agents 2015: Key Players Who Will Shine as Rookies

NFL rosters are constantly evolving and never finished, so undrafted free agents may not start on equal footing as new rookies but have the same chance to make an instant impact in training camp and OTAs. 

With 53 spots on an active roster, the competition between everyone is fierce and intense. Undrafted players are becoming an increasingly valuable trend in the NFL. Malcolm Butler went from an unknown cornerback with the New England Patriots to a Super Bowl hero in one night, for example. 

According to Mike Huguenin of NFL.com, 15 players who went undrafted made it to the Pro Football Hall of Fame. It's an uphill battle, but the many success stories for players who didn't get the honor of hearing their names called on draft weekend give hope to this year's group. 

There were many notable undrafted signings who have the talent to make an impact for their new teams. After parsing through the list of moves made by each club, here are the players in the best spot to succeed right away. 

Justin Cox, DB, Kansas City Chiefs

David J. Phillip/Associated Press

The fact Justin Cox went undrafted wasn't a surprise. He was indefinitely suspended from Mississippi State's football team in November following an arrest on domestic violence charges, per the Starkville Daily News. 

According to Brandon Walker of The Dispatch in Mississippi, Cox pled guilty to a misdemeanor trespassing charge, and the domestic violence charge was "dismissed at the victim's request," per Oktibbeha County Sheriff's Investigator Brett Watson. 

Cox's return to football occurred at the scouting combine in February. It was a mixed-bag effort for the former Mississippi State safety, though there were clear standout tools that could have gotten him drafted if there were no baggage. 

The negatives, which Deion Sanders points out (h/t Dion Marino of DraftBreakdown.com), included a general lack of coordination:

Marino is right that straight-line speed alone doesn't lead to success in the NFL, but Cox tested well in other areas at the combine. He measured in at 6'1", 191 pounds with that 4.4 speed, a vertical jump of 38 inches, broad jump of 129 inches and 20-yard shuttle in 4.07 seconds. 

David J. Phillip/Associated Press

There are power and agility in Cox's game that Andy Reid's coaching staff can work with. He's got to make an impression on special teams early to get a roster spot, but with proper development of technique, there's no reason to think he can't play a role in a secondary that needs depth. 

The Chiefs didn't draft a safety this year, though they did grab two cornerbacks in Marcus Peters and Steven Nelson. That leaves them with Ron Parker and Husain Abdullah as the projected starters. Eric Berry's playing future is uncertain as he undergoes treatment for cancer. 

Cox isn't without flaws, but there's enough raw potential there and a good coaching staff in Kansas City to help him put pieces together quickly to be a factor on this defense. 

Dres Anderson, WR, San Francisco 49ers

TROY WAYRYNEN/Associated Press

The San Francisco 49ers have spent the last two years trying to build a wide receiving corps. Anquan Boldin remains the steady presence in the group, and former Baltimore Ravens teammate Torrey Smith joins him in 2015. 

Beyond those top two, Colin Kaepernick's weapons are an unproven lot that includes Bruce Ellington, Quinton Patton and Jerome Simpson. Depth will be critical for San Francisco this year if Kaepernick is going to develop more as a pocket passer. 

One name to keep an eye on is Dres Anderson, whom the 49ers signed out of Utah after the draft. His 2014 season ended in October due to a knee injury, at which time he had 355 yards and four touchdowns on 22 receptions. 

Lance Zierlein of NFL.com wrote that Anderson has an almost-fearless style of play that allows him to make catches in traffic:

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Possesses eye-catching second gear to separate in space. Plays bigger than listed size. Aggressive, effective run blocker. Doesn't fear the middle of the field. Adjusts well to low throws. Creates additional space with smart hand usage at top of routes. Can throttle down and get feet down near sideline. High-pointer with necessary body control. Will adjust routes to benefit quarterback. Has feel to negotiate traffic after the catch. NFL bloodlines.

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To succeed as a wide receiver in the NFC West, a player has to be willing to get hit. Seattle, St. Louis and Arizona are going to punish the opposition, so Anderson's ability to stick over the middle will give him an edge over most young wideouts. 

Zierlein did note that Anderson's drop percentage (18.6) does not help him. That is far too high for a player fighting an uphill battle to make a roster, but as long as he can make the most basic of catches early while learning the game, he will be fine. 

The 49ers can afford to take chances with a player such as Anderson as they try to shore up their receiving corps heading into 2015. 

Nick Marshall, CB, Jacksonville Jaguars 

There may not be a better spot for Nick Marshall to play than Jacksonville. The front office has been all over the former Auburn quarterback going back to the Senior Bowl, as general manager Dave Caldwell raved about him (h/t Chadd Scott of Sports Day Now):

In addition to that rave review, Chase Goodbread of NFL.com wrote that Marshall boasts the kind of measurables Jaguars head coach Gus Bradley wants in a cornerback prospect:

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Don't think for a minute that the former Auburn quarterback didn't make a strong impression on coach Gus Bradley at the Senior Bowl, when he shelved his quarterback career before the first practice to embark on a tricky position switch to cornerback. Marshall has the length and size (6-1, 210) that Bradley likes in his corners and could be a nice special-teams addition while he shakes the rust off his three-year layoff from the position.

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The fact that Marshall has experience playing the position, even if it hasn't happened since 2011, also helps because his learning curve won't be as steep as it would be if he were trying it for the first time. 

Before taking over as head coach of the Jaguars, Bradley came from a situation in Seattle that was rife with talent in the secondary. He was the defensive coordinator when players such as Richard Sherman, Kam Chancellor and Earl Thomas were evolving into the Legion of Boom. 

That's a high bar for Marshall to climb, though he's physically in the same category as a 6'1", 210-pound player with arms measuring over 32 inches. He's not going to turn into Sherman, Chancellor or Thomas because those players are freaks. It just speaks to what Bradley can turn quality talent into.  

But getting a long, lean cornerback who has shown a willingness to learn a different position if it gets him into the NFL speaks to Marshall's character. Jacksonville isn't overflowing with talent right now, so the 22-year-old should get a chance to play on special teams early. 

The Jaguars can work Marshall into the defensive rotation as the 2015 season moves along. It will be a slow journey to make him more than just a special teams contributor, but the work of everyone involved will pay dividends. 

Note: Measurables via NFL.com