Lamar Jackson is a boom-or-bust player heading into the 2018 NFL Draft

We’ve got a nice mixture of boom-or-bust candidates to look at heading into the 2018 NFL Draft. These young men appear to have all the physical tools to make a huge positive impact on the league, but questions remain about whether they will be dynamic pros.

Every player that enters the NFL from college is somewhat of an unknown quantity — top picks often end up as busts, while undrafted guys have made the Hall of Fame. But there are some prospects who stand out as being particularly hard to predict, likely to either blow up in the best possible way or fizzle out with a whimper.

These are the guys who fit this mold heading into the 2018 NFL Draft.

Rashaad Penny, running back, San Diego State

The top running back in college football last year, Rashaad Penny was pretty much unstoppable for most of the past two seasons at San Diego State. Between 2016-17, he rushed for 3,266 yards and 34 touchdowns on just 425 carries, averaging 7.68 yards per carry. That’s some seriously gaudy production.

Penny isn’t a small back, either, at 5-foot-11 and 220 pounds. And he proved some folks wrong about his speed at the combine, running his 40 in 4.46 seconds, which is much faster than was anticipated. Still, it’s so tough to gauge how his game will translate to the NFL. He played in the Mountain West and struggled during the two games the Aztecs played against Fresno State and Boise State — the top two defensive teams in the conference — gaining just 122 yards on 36 carries in those two games last year.

So, is he going to be the next underrated back to tear up the NFL? Or will he end up struggling to break tackles against NFL defenders and prove to be a better short-yardage back than a home-run threat? That’s what we’ll soon find out about this extremely intriguing player.

Josh Jackson, cornerback, Iowa

There wasn’t a cornerback in college football who had a better season statistically last year than Josh Jackson. He picked off eight passes and, according to Pro Football Focus, allowed a passer rating of just 36.5 when targeted on 91 passes in 2017, the best mark in the FBS.

There’s a lot to like about Jackson’s game. He’s long and tall, coming in at 6-foot-1 and 192 pounds. He appears to be a natural ball hawk and has above-average instincts. But he’s also not as fast as some other top corners this year, having run his 40 in 4.56 seconds. Furthermore, Jackson could end up being one of those one-year-wonders who gets overdrafted. He only had one big-time year at Iowa and comes into the NFL with just 14 career collegiate starts.

So, as much as it’s easy to fall in love with Jackson’s game, the jury is still out on how effective he’ll be when it’s time to go up against NFL quarterbacks and receivers.

Kolton Miller, offensive tackle, UCLA

As we mentioned at the conclusion of the combine, Kolton Miller was one of the guys who really upped his stock at Lucas Oil Stadium. He’s huge, coming in at just under 6-foot-9 and 309 pounds. For a big guy, Miller’s athleticism stands out as a cut above the rest in this year’s class — one that’s very sketchy at the offensive tackle position. Miller set a new combine record for offensive tackles with a broad jump of 10-foot-1. He also jumped 31.5 inches in the vertical and posted the third-best 40 time of any offensive lineman (4.95 seconds).

The big issue here is that Miller was extremely up-and-down for the Bruins. He is very inconsistent and struggles with technique at times, so he’s not likely going to come into the NFL right away and dominate.

The way he’s risen up the board in recent weeks reminds this scribe of how Eric Fisher became a top target in the 2013 NFL Draft. Now, Miller’s not in play for the top pick like Fisher was that year, but he could certainly find himself being called to the podium in Round 1 this upcoming April.

Donte Jackson, cornerback, LSU

You cannot teach raw speed, and LSU cornerback Donte Jackson has it. He didn’t break the combine record like he wanted to but still tied for the fastest time of any player at the 2018 NFL Scouting combine, running his 40 in 4.32 seconds.

A player many consider to be a fringe first-round pick, Jackson has the potential to be a big draft riser in the mold of Adoree’ Jackson. He is a small cornerback, coming in at just 5-foot-11 and a paltry 175 pounds, and he showed himself to be pretty darn weak putting up just seven reps on the bench at the combine. Of course, some teams will likely fall in love with how loose his hips are and how effortlessly he closes when the ball comes his way.

Still, it’s not hard to see Jackson ending up as a big disappointment in the NFL.

Orlando Brown, offensive tackle, Oklahoma

The biggest loser from this year’s combine, Orlando Brown hurt himself in a big way. He was exceedingly slow, showed up very weak on the bench, couldn’t jump to save his life and was yelled at by coaches for loafing (more on all that here).

Though, after all that went down none other than Baker Mayfield came to Brown’s defense, with a pretty compelling argument, we might add.

“When are you going to watch Orlando Brown run 40 yards down the field?” Mayfield said (h/t Houston Chronicle). “Never. Look at his film. He gave up zero sacks last year.”

Brown is flawed, to be sure. He’s top heavy and tends to lunge at defensive linemen, which will not work out well against elite pass rushers in the NFL. But at the same time, his size, length, ability to absorb blockers and keep his quarterback clean are attributes that will continue to intrigue teams. Despite his poor combine showing, Brown could still become a darn good, if not dominant NFL offensive tackle.

Calvin Ridley, wide receiver, Alabama

Talk about an intriguing player. Coming into the combine, many pegged Ridley as the clear-cut top receiver in this year’s draft class. However, that was mostly because the rest of this year’s receivers are more promise than polish, and because Ridley showed the ability to make big plays downfield during his tenure with Alabama.

However, despite running a decent 40 time of 4.43 seconds for a man his size (6-foot and 189 pounds), Ridley was downright disappointing the rest of the way at the combine. He jumped poorly, wasn’t particularly impressive in the 3-cone drill and struggled on the field, especially during the gauntlet run.

Factor in the fact that Ridley is older than many of the top prospects this year (23), one wonders if NFL cornerbacks will feast on this young man, who might have been akin to a big fish in a little pond during his career with the Crimson Tide.

Arden Key, EDGE, LSU

Arden Key looks the part of an elite NFL pass rusher. He showed up to the combine weighing in at 238 pounds, which is darn lean for his 6-foot-6 frame. He also showed some tremendous quickness in the 3-cone drill and short shuttle, not to mention some outstanding lateral movement on the field drills.

However, Key also shocked folks by abstaining from running the 40 and working on the bench press. He also was unimpressive in the jumps, showing average raw explosion. Factor in the fact that he bugged out on his team last year and was also dealing with injuries, and that he’s had some wild fluctuations in weight over the course of his career, and there are some red flags to consider for NFL teams as they weigh the pros and cons of drafting this young man.

Baker Mayfield, quarterback, Oklahoma

Baker Mayfield

Is Baker Mayfield the next Russell Wilson/Drew Brees type, or is he just another short quarterback who cannot cut it at the professional level? There are some serious concerns about whether he’ll adapt to a pro-style system, too, as Mayfield was under center for just 4.8 percent of all snaps in 2017, per Daniel Jeremiah of NFL.com.

When it comes to accuracy, Mayfield is on another level compared to his peers in this year’s draft class. He also has excellent anticipation and has a natural feel for how to avoid having his balls batted down at the line of scrimmage. But NFL personnel folks are going to have to figure out whether that was due to the Air Raid system at Oklahoma or because Mayfield is just that darn good.

Personally, I’m not betting against this young man to be a winner in the NFL. But there are legitimate reasons to think he won’t become a franchise passer, too.

Marcus Davenport, EDGE, UTSA

When you look at Marcus Davenport, you see an explosive athlete who has the potential to evolve into an All-Pro defensive end at the NFL level. But potential is a dangerous word that has gotten many an NFL general manager fired from his post, too.

Physically, Davenport has everything you look for in an elite pass rusher. He’s tall, at 6-foot-6 and 264 pounds, has a tremendous 80-plus inch wingspan and has elite quickness. His 4.58-second 40 time was the second-best among defensive ends at the combine, and he posted a 1.63-second 10-yard split, which is fabulous.

However, it’s important to note that Davenport played at a small school and went against lesser competition. Yet he still didn’t post the dominant sack totals you’d expect from a player with his potential. In four years at UTSA, playing in 43 games, Davenport tallied just 21.5 sacks. So, is he just a physical freak or did what he showed at the Senior Bowl point to bigger things in the NFL?

D.J. Chark, wide receiver, LSU

It’s not D.J. Chark’s fault he played at LSU the past three years. The Tigers are perennially one of the worst passing teams in the SEC, and the past two years when Chark was starting were no different. Because of that, he caught just 66 passes for 1,340 yards and six touchdowns in 2016 and 2017, combined.

With all that said, teams have to be salivating over what Chark brings to the table. He was one of the biggest winners at the combine, posting obscene marks in the 40 (wide-receiver best 4.34 seconds), vertical (40 inches) and broad jump (10-foot-9). So, what you see on tape — a guy who has elite deep speed and who can go up and get passes — showed up at the combine, too.

The thing is, Chark isn’t very big (6-foot-3 and under 200 pounds) and will have a tough time getting past physical press corners at the NFL level. So, despite his freakish athleticism, there’s a good chance this LSU product will struggle to find his footing as a professional, especially if he lands in the wrong situation.

Josh Sweat, EDGE, Florida State

Much like we discussed with Davenport, Josh Sweat didn’t put up the kind of production at Florida State you’d expect to see out of an elite pass rusher. He tallied just 14.5 sacks in three seasons with the Seminoles, and he wasn’t particularly dominant against the run, either.

His combine was off the charts, however, as he drew comparisons to guys like Jadeveon Clowney and Ziggy Ansah. In particular, his 10-yard split of 1.55 seconds is something you don’t normally see from guys who aren’t elite speed receivers.

It’s going to be fascinating to see if a team takes a big gamble on Sweat early in the draft. His tape and college production don’t warrant an early pick, but that elite athleticism could be too enticing to pass up for teams needing big impact on the edge.

Lamar Jackson, quarterback, Louisville

Disclaimer: Count this scribe among those who think Lamar Jackson is going to blow up at the NFL level.

With that out of the way, I’d be foolish to ignore the possibility that Action Jackson could also be a huge flop in the mold of Robert Griffin III. He’s not as big as some of the other quarterbacks, coming in at just over 6-foot-2 and 216 pounds. He’s also not a polished quarterback — he has a lot of work to do mechanically, especially with his base and his footwork.

Still, you cannot teach the freakish athleticism and raw speed Jackson possesses. And his arm strength is more than adequate to make every throw in the book. Jackson’s success at the NFL level likely will come down to whether he lands in the right situation with coaches who appreciate his attributes and have a solid plan for putting them to work.

Malik Jefferson, linebacker, Texas

Malik Jefferson showed up very well at the combine, which was predictable. He ran his 40 in 4.52 seconds, which was third-best among linebacker and posted 27 reps on the bench, which was second-best in his position group. He posted strong totals in both jumps as well, and he looked good on the field.

Unlike some of the other top linebacker prospects in this year’s draft, Jefferson is more of an attacking, downhill threat than he is a read-and-react player. Lacking strong instincts, he’s much better when he has a specific assignment and can just let his elite athleticism loose, rather than making split-second decisions on the fly.

So, whether Jefferson finds success in the NFL or ends up as a bust likely depends on being drafted into the right system.

Josh Allen, quarterback, Wyoming

Josh Allen is one of the most intriguing players attending the 2018 NFL Scouting Combine

Perhaps the biggest boom-or-bust prospect in this year’s draft, Josh Allen brings the biggest arm in a generation to the table. And the hype surrounding him right now is so far off the charts it’s becoming ridiculous, especially considering his college production at Wyoming.

We’re talking about a kid who completed just 56.2 percent of his passes the past three years. Typically, quarterbacks who struggle that badly in college don’t get better in the NFL, where throwing windows get so much tighter and everyone is faster and smarter.

Still, Allen looks the part of an elite NFL quarterback when you get him in a controlled environment. He has outstanding size (6-foot-5 and 233 pounds), is a natural athlete who can effortlessly take deep drops and has the speed to evade pressure when it comes. Teams picking at or near the top of the draft in need of a quarterback will have to talk themselves out of selecting Allen, who could be the league’s next legend or the next monumental bust.

Jesse Reed
Managing Editor at Sportsnaut. Featured on Yardbarker and MSN.com, and formerly was a breaking news writer/NFL analyst for Bleacher Report.