The evolution of the passing game in the NFL has forced coaches and scouts to alter the job description for linebackers. Teams are intent on identifying disruptive playmakers with the speed and quickness to harass the passer, while also possessing the athleticism and instincts to drop into coverage.

At outside linebacker, in particular, evaluators are searching for versatile edge players capable of playing from an upright position on early downs before putting a hand in the dirt to rush the passer on third down. The proliferation of the 3-4 defense and exotic sub-packages has made the linebacker the designated pass rusher for the majority of teams, spawning a hybrid position that is suddenly in high demand.

Looking at this year's class, there are several players capable of fitting the bill as hybrid players on the edge. South Carolina's Melvin Ingram sits atop the board with his impressive all-around physical attributes. He wreaks havoc off the edge with spectacular first-step quickness, and few blockers are capable of handling his inside spin move.

Alabama's Courtney Upshaw and Clemson's Andre Branch are also dangerous edge rushers with the quickness and burst to hunt down quarterbacks. Both are capable of turning their speed into power, and their relentless motors lead to sacks off extra effort. While scouts will pick apart small aspects of each player's respective game, this week's NFL Scouting Combine should showcase their skill and potential as pros.

On the interior, scouts are placing a premium on linebackers capable of affecting the passing game from alignments within the tackle box. More teams are willing to add smaller, quicker linebackers with the athleticism to blitz off the edges and also play an integral role in coverage.

Although the top candidates on the board -- Boston College's Luke Kuechly, Alabama's Dont'a Hightower and Arizona State's Vontaze Burfict -- have reels of game film suggesting they are capable of acting as difference-makers against the pass, questions about their speed and athleticism make their combine performance in a battery of drills critical to their eventual draft position. Their respective performances on the field turf at Lucas Oil Stadium could alter the landscape of the draft's early rounds.

Hybrid Linebackers

1. Melvin Ingram, South Carolina: Ingram has been a fast riser on draft boards across the NFL since emerging as one of the SEC's most dominant defenders in the fall. His combination of speed and athleticism overwhelms edge blockers, and his remarkable first-step quickness makes him nearly impossible to block in isolated matchups. He flashed glimpses of his disruptive potential during Senior Bowl practices, cementing his standing as one of the top defenders in the draft. With a solid workout at the NFL Scouting Combine, Ingram could vault into top-10 consideration on draft day.

Good fits: Carolina Panthers, Miami Dolphins and Buffalo Bills.

2. Courtney Upshaw, Alabama: Upshaw doesn't display the flashy game of some of his contemporaries, but it is hard to dispute his production and effectiveness as an edge player. He shows an uncanny knack for getting to the quarterback, despite routinely facing extra attention from running backs in pass protection. He is equally effective against the run, displaying strength and power at the point of attack. Although there are questions about his overall athleticism and speed, Upshaw can render those concerns moot with a strong performance in Indy. If he is able to post numbers that fall within the average at the position, evaluators will trust that his exceptional play in big games will translate to immediate success as a pro.

Good fits: Arizona Cardinals, New York Jets and San Diego Chargers.

3. Andre Branch, Clemson: Pass rushers with explosive first-step quickness are coveted due to their ability to put immediate pressure on the quarterback off the edge. Branch is one of the best I've seen in college football at defeating blockers with speed around the corner. His combination of athleticism and burst is hard to find. To solidify his place as a potential first-round selection, Branch must show the size, strength and power to be an effective edge player as a pro. If he can pass the eyeball test at the weigh-in and post respectable numbers on the bench press, while displaying explosive athleticism in drills, Branch will surge up draft boards.

Good fits: New England Patriots, Green Bay Packers and New York Jets.

4. Zach Brown, North Carolina: If you're looking for a workout warrior, place your bet on Brown. He is the most impressive athlete at the position and his remarkable speed will certainly catch the eyes of scouts. Having shown impressive flashes of disruption as a pass rusher, Brown has the potential to experience a meteoric rise up the big board with a strong performance at the combine. If he can exhibit a strong football IQ to erase doubts about his instincts, Brown could put a stronghold on a spot within the first round.

Good fits: Seattle Seahawks, Cleveland Browns and New Orleans Saints.

5. Vinny Curry, Marshall: Curry is a high-motor pass rusher generating a strong buzz in scouting circles with his exceptional rush skills. His combination of first-step quickness and sneaky athleticism routinely leads to disruptive plays off the edge. He put those skills on display with a solid performance at the Senior Bowl. Although Curry's game remains rough around the edges, he can sell evaluators on his immense potential with a solid showing in Indianapolis. With better-than-average times in the 10-yard split and various agility drills (pro agility shuttle and three-cone drill), Curry could land among the top-40 selections on draft day.

Good fits: Carolina Panthers, Tennessee Titans and Miami Dolphins.

Sleeper to watch: Bruce Irvin, West Virginia. Irvin was considered a prime candidate to emerge as one of the top pass rushers in college football this season, but didn't get off to a fast start and seemingly fell off the radar in scouting circles. However, he finished the season with six sacks in his last five games and started to become the disruptive force scouts envisioned prior to the season. While his size and football IQ have been questioned, an excellent display of speed and athleticism could prompt evaluators to overlook his unrefined game and gamble on his developmental potential.

Good fits: Green Bay Packers, New York Jets and San Diego Chargers.

Traditional Linebackers

1. Luke Kuechly, Boston College: The most productive defender in college football possesses all of the instincts and intangibles scouts covet in a middle linebacker. Kuechly's exceptionally high football IQ allows him to play faster than his counterparts, leading to a host of big plays and hits. Although his production and leadership skills have made him a favorite in the scouting community, he will need to display the requisite athleticism and movement skills to retain his top spot at the position. If he posts a respectable 40 time and displays better-than-anticipated agility, Kuechly will garner serious consideration as a top-15 selection.

Good fits: Philadelphia Eagles, Kansas City Chiefs and Seattle Seahawks.

2. Dont'a Hightower, Alabama: Hightower will be one of the most scrutinized defenders in Indy, despite anchoring the most dominant defense in college football. Scouts have concerns about his ability to man the middle of an NFL defense at his current size (6-foot-4, 260 pounds). Although his superb instincts and hard-hitting style would appear to make him an ideal fit as a run stuffer in a 4-3 or 3-4, the NFL's emphasis on the passing game will test his athleticism and movement skills in space. If Hightower can convince scouts and coaches he possesses the agility to stay on the field in passing situations, he could be a viable option for a team looking for a big-bodied headhunter on the interior.

Good fits: New York Giants, Pittsburgh Steelers and San Diego Chargers.

3. Vontaze Burfict, Arizona State: Burfict is the most intimidating defender in college football, but concerns about his character and emotional makeup have caused him to slide down draft boards across the league. Evaluators have doubts about his ability to control his emotions on the field after watching him draw a number of personal foul penalties throughout his career. In addition, the rumors of his alleged run-ins with teammates and coaches have raised red flags from personnel men worried about bringing a disruptive player into the locker room. With so many character concerns attached to his name, Burfict must address his issues in interviews with coaches and scouts. How well he demonstrates his maturity and leadership ability in those conversations could determine his ability to remain on the draft board for several teams across the league.

Good fits: Baltimore Ravens, New York Jets and Philadelphia Eagles.

4. Sean Spence, Miami: Spence's athleticism and speed make him a hot commodity for defenses in need of an explosive run-and-chase playmaker, but concerns about his size (6-0, 224) have prompted some teams to downgrade him on their draft boards. Spence can force scouts to reconsider their projections on him by displaying explosive speed and quickness in drills. If Spence impresses while working out in shorts, he can cement his spot as a Day 2 prospect.

Good fits: Carolina Panthers, New Orleans Saints and Seattle Seahawks.

5. Bobby Wagner, Utah State: Wagner is not well-known on the national scene, but his workmanlike game has earned considerable admiration in the scouting community. He emerged as one of the best defenders in the WAC this season, displaying quickness, athleticism and toughness from his weakside linebacker spot. He shows fantastic instincts and awareness hunting down ball carriers, and scouts have been impressed with his ability to step up his game in critical situations. Following a solid showing at the Senior Bowl, he is positioned as a Day 2 possibility, but an impressive workout at the NFL Scouting Combine could solidify his status within the first three rounds.

Good fits: Philadelphia Eagles, New York Giants and Chicago Bears.

Sleeper to watch: James-Michael Johnson, Nevada. Teams searching for a solid football player to plug into the middle of the defense will study Johnson extensively during his four-day visit to Indianapolis. The former Nevada star started to generate some buzz with his solid play at the Senior Bowl, and further tape study has scouts intrigued about his potential to develop into a first-rate starter at middle linebacker. If Johnson can put on a dazzling display of speed and athleticism during the workout, while also impressing coaches with his football IQ in interviews, he could enjoy a significant rise up the charts heading into the draft.

Good fits: Atlanta Falcons, Detroit Lions and Seattle Seahawks.