5 Undrafted Free Agents Who Continue to Make a Big Impact as Rookies

An NFL player's draft status doesn't determine his career. It's merely the starting point.

The league is littered with talented participants who weren't drafted. As with any rookie class, there will always be those who rise above the biases against those who didn't warrant a valuable selection. 

Not everyone can successfully navigate the road less-traveled, though. When they do, a special person emerges on the other side. 

Ideally, every young football player would love to hear his name called on draft weekend, but only 253 had the pleasure of doing so this past spring. 

Others are overlooked for numerous reasons. Either they're not big or fast enough, hail from a small school, suffered injuries or whatever trait didn't fit the league's prototypical standards. Despite these perceived limitations, dozens of undrafted free agents still made active rosters. 

Of course, players such as Dallas Cowboys running back Ezekiel Elliott, San Diego Chargers defensive end Joey Bosa and Philadelphia Eagles quarterback Carson Wentz garner the most attention. After all, each was selected among the top five players in April and experienced early professional success. 

There are others who weren't as fortunate yet earned their playing time and overcame the odds to become instant-impact performers. Five stand above the rest for exemplary performances through the first 14 weeks of play. 

Running Back Robert Kelley, Washington Redskins

The man affectionately known as "Fat Rob" would receive far more attention if Elliott wasn't leading the league in rushing and playing in the same division. However, Robert Kelley is third among rookies with 587 rushing yards. The first-year runner is also tied for sixth overall with an average of 4.6 yards per carry. 

Since taking over as the team's starter in Week 8, the Tulane product averaged 80 yards per game—which is nearly a 15-yard-per-game improvement over the team's previous starter, Matt Jones.

Nick Wass/Associated Press

Kelley's teammates saw how talented he was upon his arrival in the nation's capital. 

"As far as running the football, very talented runner, and we knew that," quarterback Kirk Cousins said, per CSN Mid-Atlantic's JP Finlay.

At 228 pounds, the rookie is a powerful and decisive runner. He's going to get downhill and try to run through every single tackle, as seen Sunday in Washington's 27-22 victory over the Philadelphia Eagles, per the NFL's Twitter feed: 

Yet, the running back almost didn't make it through college let alone becoming a starting NFL running back. 

"A few times I thought about not doing it no more," Kelley said, per ESPN.com's John Keim. 

The talented player didn't take his schoolwork seriously, he missed the 2014 season after being charged with simple battery and robbery (those charges were later dropped) and saw the head coach who recruited him fired. 

Kelley's persevered through adversity and bettered himself by losing 20 pounds after rushing for only 232 yards as a senior. The Redskins scouting staff saw something in the runner. 

"I think when you're a rookie and undrafted … what you need is belief," Cousins said, per the Washington Post's Rick Snider. "You need people around you who believe in you and have confidence in you, because he does have the talent and he can run the football well."

With two talented rookie backs in the NFC East, division opponents will need to counter the dynamic Elliott and pile-driving Kelley. 

Safety Andrew Adams, New York Giants

New York Giants safety Andrew Adams already experienced the pain most undrafted free agents endure when he was released by his current team. That Giants re-signed him to the practice squad, and he's since became a starter and one of the league's best safeties. 

Calling Adams one of the league's best safeties isn't an exaggeration. 

According to Pro Football Focus, the first-year defensive back leads everyone at his position with an average of 92.3 snaps per reception allowed. He's also first in allowing only 0.09 yards per coverage snap. Adams allowed a league low four receptions among starting safeties through 14 weeks. 

Bill Kostroun/Associated Press

"Confidence level. Confidence," Adams said of the difference from early in the year until now, per ESPN.com's Jordan Raanan. "Your first game, it’s different than preseason and what not. ... Now, it's just being able to see and react rather than think about should I do this or that. You just play faster."

The safety suffered from not standing out during his collegiate career despite starting 33 career games, being a team captain and leading his team in multiple categories as as senior.

He even tested well at UConn's pro day. NFL Draft Scout provided his workout numbers. By comparing those numbers with the safeties who actually attended the NFL combine in Indianapolis, Adams would have finished among the top 10 performers in every major event except broad jump. 

The signs were present to show how effective Adams could be at the next level, but they were overlooked. He wasn't the only defensive back to fall into this category, either. 

Cornerback Brian Poole, Atlanta Falcons

Over the last few seasons, the Atlanta Falcons defense struggled. Even with Desmond Trufant's emergence into one of the game's premier cornerbacks, the team's pass defense hasn't finished among the top half of the league over the past three seasons. 

The group continues to struggle, but they're finding the pieces to develop into a very good unit. Trufant is only the starting point (although, he's on injured reserve at the moment). The team recently signed Robert Alford to a four-year, $38 million contract extension. 

Harry How/Getty Images

Those two have been on the roster since 2013, though. This season, the organization found another vital piece to the puzzle in nickel corner Brian Poole. 

"He was undrafted so he has a chip on his shoulder," Alford said of Poole, per Andrew Hirsh of the Falcons official site. "He's going out there and showing each and every Sunday, each and every practice, every day, that he deserves to be in this league. I’m proud to see the progression and the way he's improving each and every week."

According to Pro Football Focus, Poole has played the third-most snaps covering the slot. He also ranks among the league's best nickel corners is coverage snaps per target and coverage snaps per reception. 

Despite being a starting position in today's game due to the preponderance of nickel defenses, slot corners still aren't considered valuable assets. As such, a shorter-than-ideal corner who is slower than preferred yet excels working through traffic and playing multiple roles like Poole get overlooked during the draft process. 

A similar argument could have been made against another undrafted cornerback who continues to excel. 

Cornerback Briean Boddy-Calhoun, Cleveland Browns

The Cleveland Browns defense is awful. The NFL's youngest team also remains winless through 14 weeks. Yet a handful of bright spots can be found throughout the roster. The play of Briean Boddy-Calhoun tops the list. 

Cleveland didn't even sign Boddy-Calhoun after the draft. Instead, he agreed to teams with the Jacksonville Jaguars. The Minnesota product made it all the way through training camp only to be waived during the league's final round of preseason cuts. 

Jacksonville's loss became the Browns' gain. The organization placed a claim on Boddy-Calhoun, and he's developed into the team's top cornerback. 

Ron Schwane/Associated Press

The first-year defensive back isn't simply the the highest-graded rookie at his position, according to Pro Football Focus, but his performance ranks among the league's top 20 cornerbacks. 

In some ways, his play invokes the great Frank Minnifield, because he's only 5'9" but doesn't have any issues getting physical with top receivers on the outside or moving inside to the slot. 

"Real smart guy for a rookie," veteran corner Jamar Taylor said of Boddy-Calhoun, per Andrew Gribble of the Browns official site. "He's a technician. He's always trying to clean up his technique. He has great ball skills and he loves the pressure. We put him in crazy positions but the kid just always seems to make a play."

Taylor added, "I think he's going to be something to reckon with."

Undersized with one team already giving up on him, Boddy-Calhoun proved a diamond can be found even in the NFL's roughest situation. Whereas other franchises are known for unearthing top talent each and every year. 

Nose Tackle Michael Pierce, Baltimore Ravens

Baltimore Ravens general manager Ozzie Newsome is the best at evaluating talent. Nose tackle Michel Pierce is the latest example of a player completely off the radar, who already developed into a top performer. 

The Samford product (by way of Tulane) is a massive run-stuffer at 339 pounds and nearly impossible to move. Pierce owns a top-15 run grade from Pro Football Focus, yet he's played fewer snaps than any other interior defender ranked ahead of him. Only the New York Giants' Damon "Snacks" Harrison holds a better run stop percentage. 

Nick Wass/Associated Press

"He's come from really kind of an unknown," defensive coordinator Dean Pees said, per the Baltimore Sun's Mike Preston. "I can't say enough good things about him. I'm really, really pleased with where he is."

Pierce's dominance at the point of attack is derived from his low center of gravity and powerful backside. At 6'0", the rookie nose tackle owns a natural leverage advantage. Plus, he can squat 725 pounds with ease. 

"His lower body strength was always amazing," Samford defensive line coach Victor Cabral said. "He also has very strong hands and great anticipation, especially in the run game. He studied film hard and did all the things he needed to do to be an outstanding player."

When Pierce is paired with fellow nose tackle Brandon Williams, the great wall of Baltimore forms and opposing offensive lines are asked to uproot 679 pounds of humanity. 

Traits Determine Talent

Too often, obvious traits such as height, weight and speed are used to determine a player's value. Physical ability only takes an individual so far. Intangibles separate those who are successful as opposed to those who ultimately fail. 

Kelley, Adams, Poole, Boddy-Calhoun and Pierce are all different performers, yet each displays the same intangible traits to make them successful after being bypassed during the draft process. Each of these young men showed great worth ethic, a willingness to learn, football intelligence and adaptability after failure while taking advantage of their specific situations. 

Most love to watch the NFL draft. It provides great drama, and seeing young men realize their dreams can overwhelm even the most cynical person. It's the first step toward greatness, though. Those who aren't drafted either become more driven or fade into obscurity.

For the aforementioned undrafted free agents, they already made their mark while other more-heralded prospects are still trying to find their way. 

Brent Sobleski covers the NFL for Bleacher Report. Follow him on Twitter: @brentsobleski.