NFL draft: Drew Lock, Rashan Gary among 13 boom-or-bust prospects

It's not a stretch to say that at some point, the 2019 NFL draft will feature more than a few prospects who don't live up to expectations.

Even the most talented-packed classes throughout history have included their fair share of players who went on to earn the dreaded bust label. And while there's a degree of uncertainty for every player being evaluated in the transition to the pros, some prospects have a more volatile outlook than others. The difference between a fruitful career and a disappointing one can often simply boil down to matters of coaching, opportunity and scheme fit.

With all that still unsettled ahead of this year's draft, here's our look at the 13 biggest boom-or-bust prospects for 2019:

QB Drew Lock, Missouri (6-4, 228 pounds): The optimally sized passer with dazzling arm strength but questionable decision making is one of the draft's oldest recurring conundrums. Lock is the latest test for teams, which will have to decide how to reconcile his sublime physical tools with inconsistent accuracy and a confidence that can border on reckless. Maybe Lock settles into a Jay Cutler-like career as a long-term starter who confounds fans with his highs and lows, but passers with this profile tend to get their general managers and coaching staffs either lionized or fired.

RB Darrell Henderson, Memphis (5-8, 208 pounds): It's easy to see the "boom" in Henderson's game, as he averaged 8.9 yards per carry over his last two seasons and had a Football Bowl Subdivision high of 15 plays that went for more than 40 yards in 2018. Those big gains, however, won't come as easily in the NFL, where he'll have to employ more precise cuts and power when initiating contact to get past the first wave of defenders. Landing in a zone-based scheme in which he can attack the edges of the defense will be critical to his success.

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WR D.K. Metcalf, Ole Miss (6-3, 228 pounds): From his self-reported (and oft-questioned) 1.9% body fat to his 4.33-second 40-yard dash and 40 1/2-inch vertical leap, Metcalf built a Paul Bunyan-esque mythos at the NFL scouting combine. But poor marks in the three-cone drill (7.38 seconds) and short shuttle (4.5 seconds) underscored concerns about whether his build is actually a detriment to his change-of-direction skills. Perhaps the biggest question: Can he become a more complete receiver after running a limited set of routes in college, or will he primarily be a deep threat who has to beat cornerbacks by running past them or coming down with a contested catch?

WR Hakeem Butler, Iowa State (6-5, 227 pounds): Towering over his competition, Butler is an imposing figure in the red zone and on jump balls. Part of his problem, though, is winning in that manner might have to be his bread and butter, as his long strides and deliberate movements impede his efforts to break free from defensive backs. Butler will have to be more creative in his route running or risk following the same disappointing career paths as other supersized targets like Jon Baldwin and Kelvin Benjamin.

WR Parris Campbell, Ohio State (6-0, 205 pounds): What will Campbell's superlative speed (4.31-second 40-yard dash) and leaping (40-inch vertical) mean for his transition to becoming a downfield threat in an NFL passing attack? It's not completely clear, as he was pigeonholed by Ohio State's offense into running routes at or near the line of scrimmage to maximize his run-after-catch opportunities. Campbell could become a well-rounded receiver, but he's somewhat of a projection as anything beyond a gadget threat.

OT Greg Little, Ole Miss (6-5, 310 pounds): Left tackles with Little's combination of length and fluidity are rare, so it's easy to see why he was once touted as a potential early first-round pick. But inconsistency plagued him at Ole Miss, and now he might have to wait until Day 2 to hear his name called after more polished protectors in the draft. Whether he ends up a high-end starter or a backup might depend on the development of his hand usage and footwork.

DE Rashan Gary, Michigan (6-4, 277 pounds): A former No. 1 overall recruit, Gary had one of the most impressive showings of any player at the combine when he ran a 4.58-second 40-yard dash and had top marks in the vertical leap (38 inches) and broad jump (10 feet). His collegiate production (10 1/2 sacks and 24 tackles for loss in three years), however, was not that of a dominant defender, leaving questions about how much he truly grew during his time at Michigan. Even though he should be above average against the run in the NFL, his next team will expect significant production out of him as a pass rusher to justify his expected early first-round draft position.

DE Brian Burns, Florida State (6-5, 249 pounds): After bulking up 21 pounds before the combine, Burns was billed as one of the event's big winners. Now it's time for him to prove the added weight has a bearing in his play, as he still could be prone to being overpowered by offensive tackles at the next level. Burns will make his mark by pestering quarterbacks, but teams will want to see him shore up his anchoring against the run.

DE/OLB Jachai Polite, Florida (6-3, 258 pounds): In a breakout junior campaign that included 11 sacks and six forced fumbles, Polite looked to have all the trappings of a first-round prospect. Then came the combine, where he showed up 20 pounds heavier than he was listed with the Gators, ran a dismal 4.84-second 40-yard dash before pulling out with a hamstring injury and raised questions when he said the Packers and 49ers "bashed" him in interviews. While he has the potential to be a prolific pass rusher, he needs to make the right impression on his new team by proving he can be a reliable presence.

DT Dre'Mont Jones, Ohio State (6-3, 281 pounds): Like classmate Ed Oliver, Jones is an undersized yet disruptive interior lineman who should benefit from the recent success of Aaron Donald and Geno Atkins, among others. Unlike Oliver, however, he can be easily washed out in the run game when he doesn't beat offensive linemen with his first step, and his combine testing marks were pedestrian at best. He likely will only be attractive to teams that run a 4-3 defense that prizes defensive tackles who can penetrate and make plays in the backfield.

LB Mack Wilson, Alabama (6-1, 240 pounds): A star turn in the 2017 season's College Football Playoff looked to be Wilson's coronation as Alabama's next emerging star. In his lone year as a starter in 2018, though, he too often let his aggressive nature get the best of him as he overran plays and ended up out of position. Wilson still has promise as an attacking linebacker with the tools to thrive in coverage, but that skill set will do him little good if he doesn't hone his ability to read plays.

CB Lonnie Johnson, Kentucky (6-2, 213 pounds): With an impressive set of physical tools but an unrefined technique, Johnson is the kind of prospect who could entice a general manager but vex a coaching staff. His standout work in the Senior Bowl might help convince teams he's an ascending prospect with big upside in press coverage. Yet it's hard to overlook the route recognition and anticipation (only one interception in two years) issues that could make him a liability.

CB Joejuan Williams, Vanderbilt (6-4, 211 pounds): Stepping into the NFL with rare size for his position (only three cornerbacks who played in a regular-season game last year were listed at 6-3 or taller, and none weighed more than 207 pounds), Williams can smother receivers both at the line of scrimmage and when the ball is in the air. His subpar long speed and quickness, however, could allow crafty pass catchers opportunities to separate. Playing in a scheme heavy on press-man coverage will be crucial for his pro career.

Follow Michael Middlehurst-Schwartz on Twitter @MikeMSchwartz.