The players are divided into tiers of value: top 20, top 50, top 80, top 120, top 150 and top 200. Note that these are preliminary grades that will likely change based on player performance during the course of the 2015 season, as well as postseason all-star games, the NFL Scouting Combine and pro-day workouts. Some prospect ratings have changed since their initial publication due to continued study of their play as well as the evaluation of others at their position.
Jack Allen, C, Michigan State
When an NFL offensive line coach sees that a young lineman was a high school wrestler, a smile comes across his face. Grappling in the trenches is what a lineman does -- and is something at which Allen excels. The former Illinois state title holder at 285 pounds is not the largest center in the country (6-2, 295), but no other "man in the middle" matches this four-year starter's toughness, anchor, and aggressive nature.
Devontae Booker, RB, Utah
The former Washington State signee and junior-college star ran just 31 times in his first three games with the Utes in 2014 -- then he ran for 130 yards a game through the rest of the season. His combination of power, quickness, elusiveness in the hole and receiving ability give him an excitement factor lacking from most collegiate backs. The devaluation of his position might prevent Booker (5-11, 212) from being a top-50 pick, but another ultra-productive season and top-notch NFL Scouting Combine workout could push him in that direction.
Trevone Boykin, QB, TCU
Clearly one of the most electric players in college football, Boykin should make it to New York as a Heisman Trophy finalist. The problem for scouts is not his average height, but his lack of bulk. The troubles Robert Griffin III has had staying on the field during his short career will lead teams to question whether Boykin's slight frame (6-1, 208) will hold up to a next-level pounding -- especially considering he's most effective when using his feet to challenge defenses. He is capable of making plays from the pocket, however; a strong senior season and postseason work might be enough to convince a team to take a chance on him relatively early in the draft.
Pharaoh Brown, TE, Oregon
On pure talent alone, I would have included the 6-foot-6, 250-pound rising star as a top-50 selection. However, Brown suffered a gruesome injury last November against Utah, which nearly cost him his right leg. Despite missing the last five games of the season, he garnered first-team All-Pac-12 honors with 25 catches for 420 yards and six scores. If his rehabilitation allows him to resume his career this fall, and he regains the strider's speed and agility that made him one of the top pass-catchers in the country before the injury, expect him to be an early-round pick.
Ryan Brown, DE/OLB, Mississippi State
Teammate Preston Smith went from relative unknown to the 38th overall pick in the 2015 draft, and Brown has the natural ability to do the same. Smith went from 6.5 tackles for loss and 2.5 sacks as a junior to 15 and 9, respectively, in a first-team All-SEC senior campaign; Brown made seven tackles behind the line, including 3.5 sacks in 2014. Brown's frame is more slender (6-6, 262) than Smith's (6-5, 271), and his agility as a stand-up rusher might be better than Smith's, even though Smith was selected by Washington to play linebacker in its base 3-4 scheme. Brown has active and strong hands, and flashes physicality -- if he continues to improve his ability to stay low at the point of attack and his mixing up of a bull rush with counter moves, the Bulldogs will have another star in the making.
Jonathan Bullard, DE, Florida
The Gators have had a versatile defensive lineman selected in the first round in two of the last three drafts: Sharrif Floyd to Minnesota in 2013 and Dominique Easley by the Patriots in 2014. Bullard is looking to become the next in line. The 6-foot-3, 271-pound former five-star recruit has moved between end and tackle during his career, using quickness to beat guards inside and strength to hold the edge on the outside. He was fairly productive despite playing inside often as a junior (8.5 tackles for loss, 2.5 sacks); taking another step forward during the 2015 season will make him quite attractive to base 3-4 teams looking for size and agility in their five-techniques.
Kevin Byard, SS, Middle Tennessee State
Although Byard (5-11, 226) looks like a strong safety, he often finds himself in the back half of the secondary. That position has allowed him to intercept 15 passes in his 37 starts, scoring on four of them. He shows the ability to close on run plays from the deep half, as well as fill the hole and wrap up plays from behind. If he tests well, teams might take a chance on him in the top half of the draft.
Leonte Carroo, WR, Rutgers
Despite the fact he was losing his quarterback of eight years in Gary Nova (they played together at Don Bosco Prep, as well), Carroo decided to stay in college for one more year. The honorable mention All-Big Ten pick in 2014 reminds scouts of Golden Tate with his running back-type body (6-1, 200). Putting up another 1,000-yard receiving season with a new passer in Piscataway should impress scouts enough for him to end up being a second-round pick like Tate.
Ken Crawley, CB, Colorado
Since his freshman year, Crawley has used his height (6-1, 180) and long arms to distract and disrupt receivers downfield. He's broken up 21 passes during his career, intercepting two others (both in 2013). Crawley's lack of interceptions kept him from receiving honorable mention All-Pac-12 notice last year, but if he can convert turnovers as a senior, he'll be a first-team pick. Combining that improvement with additional proof of having the strength and physicality to handle NFL receivers will help him move up draft boards next spring.
Josh Doctson, WR, TCU
Doctson (6-3, 195) started his collegiate career at Wyoming before transferring back to his home state. He became Heisman Trophy candidate Trevone Boykin's favorite target (65 receptions, 1,018 yards, 11 TD) by finishing routes inside, turning short routes into long gains, as well as getting deep. Once he gets down the field, he can separate using his length and speed, and shows an uncanny ability to track the ball over either shoulder. If physical enough for scouts' liking, Doctson could be this season's Kevin White.
Kyle Fackrell, OLB, Utah State
A stand-up rush linebacker (6-5, 245) with length and agility, Fackrell came out the box strong for the Aggies, garnering all-conference honors in each of his first two seasons on campus (21 tackles for loss, eight sacks in 2012-2013). Fackrell suffered a torn ACL in the season opener last year, and now must prove he is strong enough to handle NFL linemen and healthy enough to stay on the field. If he does, look for him to climb into the second or third round.
Kris Frost, OLB, Auburn
Frost displayed a solid all-around game in his first year as a starter in 2014, moving well for his size in coverage (one interception, three pass breakups). He also served as an effective blitzer (10 tackles for loss, 3.5 sacks), slipped blocks between the tackles and hustled down plays from behind (85 total stops). He'll improve his stock even more if he displays a more consistent physicality against blockers during his senior campaign.
Joshua Garnett, G, Stanford
Garnett, the son of an NFL nose tackle (Scott Garnett), played next to 2015 first-round pick Andrus Peat on the left side of Stanford's line last fall. His combination of size (6-5, 325) and movement are jaw-dropping -- especially when he takes an occasional turn as an H-back. The fourth-year player will get his turn to shine in his last season on The Farm now that Peat has moved on ... and scouts will take notice.
Joe Haeg, OT, North Dakota State
Every draft since 2010 has seen at least one offensive lineman from a non-FBS school drafted in the top 100. Haeg (6-6, 299) is this year's best candidate, as the All-American hopes to follow in his former teammate's shoes; tackle Billy Turner was drafted in the third round by Miami in 2014. Haeg possesses the requisite size and length, as well as very good mobility and a growing frame that teams will project to become NFL-caliber in short order.
Tyler Johnstone, OT, Oregon
Johnstone suffered a knee injury in Oregon's 2013 Alamo Bowl win over Texas. He and his doctors thought an offseason of rehabbing would heal it; unfortunately, his ACL didn't agree. He sat out the 2014 season but is expected to be back at full strength this season. Using his time off last year to add bulk (he's now listed at 6-6, 295) might pay off in the end, especially if he utilizes his athleticism to the fullest as a senior by keeping active feet and hands in pass protection.
Karl Joseph, SS, West Virginia
In a complete lack of respect for his own body, Joseph flies into the backfield and attacks receivers in space like few others in this draft class. Yet, he has started every game for the Mountaineers since arriving on campus in 2012. Joseph (5-11, 197) has a chance to fly up boards by proving his coverage skills to scouts during the 2015 season and postseason. He'll also need to show fluid hip movement and change-of-direction ability at the combine. Combining that sort of athleticism with his excellent hitting and tackling skills (92 stops in a first-team All-Big 12 junior campaign) could push him even higher on team draft boards.
Bronson Kaufusi, DE/OLB, BYU
This two-sport athlete experimented on the hardwood in 2012-13 before turning his full attention to the gridiron. His size (6-7, 263) and athleticism have allowed Cougars coaches (of whom his father, Steve, is one) to play him inside and outside during his career. He's broken up 12 passes over the past two seasons and taken an interception in for a score. He also has racked up 15.5 career sacks. If Kaufusi tests well at the combine, look for him to be drafted in the top 40 like former Cougar Kyle Van Noy (2014, Detroit).
Cody Kessler, QB, USC
Physically, there's nothing special about Kessler; he possesses average size (6-1, 210), an adequate arm, and fair mobility once outside the pocket. However, his natural intelligence within the pocket and being coached up by Trojans head coach Steve Sarkisian should count for something. Kessler hasn't turned the ball over much (just five interceptions versus 39 touchdowns in 2014), looks off safeties to find the open man on the other side of the field, and moves within the pocket to buy time and find a secondary target. If he gets good marks as a leader from his coaches, NFL scouts will consider him a potential starter at the next level.
Mike Matthews, C, Texas A&M
At 6-foot-2, 285 pounds, Matthews does not have the height and length of his father, Pro Football Hall of Famer Bruce Matthews, or his brothers Jake (the sixth overall pick in the 2014 draft) and Kevin (former Aggies center). Nor is he an elite athlete like his Pro Bowl linebacker cousin, Clay. But he has the family gene for football toughness and intelligence, a strong anchor, and nimbleness in tight spaces, which is most crucial for the center position. Some NFL teams won't have interest in him because of his lack of size, but another squad will find a reliable starter.
Cassanova McKinzy, ILB, Auburn
McKinzy took over the middle of Auburn's defense in 2014 after starting on the weak side as a sophomore -- and the move seemed to suit him just fine. The 6-foot-3, 253-pound downhill player makes life difficult for SEC running backs between the tackles (91 tackles, 11 for loss in 2014), but he also possesses enough speed to cut plays off on the sideline. Teams will likely consider him in the class of Mississippi State's Benardrick McKinney, who was a second-round pick in 2015.
Eric Murray, CB, Minnesota
Though not quite as much of a pounder as fellow top senior corner prospect Danzel McDaniel, Murray's size (6-0, 196) and physical nature should land him near the top of NFL teams' cornerback wish list. The second-team All-Big Ten selection's experience in press-man coverage is extensive, and his ball skills are good enough to create turnovers when given the opportunity. He's also a special-teams stalwart who blocked two punts in 2014, which will only increase his impact on Sundays as a rookie.
Joshua Perry, OLB, Ohio State
The Buckeyes' leading tackler in 2014 (124, 8.5 for loss, three sacks) earned honorable mention All-Big Ten honors in his second year as a starter. He's often used in a stack formation in Urban Meyer's defense, but his strength and length (6-4, 254) on the outside portends an NFL future as a 3-4 pass rusher. Showing scouts those pass-rush skills this fall, to go along with his ability to hold the edge against the run and chase down plays from behind, will only help his draft stock.
Jimmy Pruitt, CB/S, San Jose State
A versatile defender who has started at corner and safety for the Spartans, Pruitt even lined up with the first-team defense at corner as a true freshman. Though not a huge hitter, Pruitt (6-0, 203) is dependable as a tackler in space. He possesses fair ball skills (three interceptions, seven pass breakups in 2014) but, just as importantly, doesn't give up on plays even if the receiver seemingly has an advantage downfield. Pruitt's best fit is likely as a press corner, but he could project to a cover safety if his new team has a need there.
Sheldon Rankins, DT/DE, Louisville
In the Cardinals' three-man front, Rankins presents issues for both interior and outside blockers. His only start as a sophomore was in the team's bowl game, but he came on strong last season in the team's first year in the ACC (13.5 tackles for loss, 8 sacks). Rankins' (6-2, 303) versatility as a potential starting five-technique or three-technique makes him a fit in any system, which means you'll hear a lot more about this guy leading into the 2016 draft.
Brandon Shell, OT, South Carolina
Yes, Brandon is the great nephew of Pro Football Hall of Famer Art Shell. But it wouldn't matter if he was instead a relative of early television-era star Art Carney ... he simply looks like an NFL right tackle (6-6, 327), a spot which he's held down since his redshirt freshman season. It looks like he's suited to play right tackle in the NFL due to average footwork in pass protection, which would prevent him from moving into the late first or early second round. But if you want a strong-side tackle who can move the line of scrimmage (he will take smaller defenders 10 yards downfield once locked on) and still reach second-level defenders, then Shell's your man later on the second day (Rounds 2-3) of the draft.
Eric Striker, OLB, Oklahoma
Each year there is a highly productive but undersized (6-0, 223) linebacker prospect in the draft, and the question is always the same -- "is he too small?" A team will find room for Striker because of his explosiveness to the ball, though it won't be as easy timing the snap count to reach the backfield (17.5 tackles for loss, 9 sacks in 2014) in the NFL. He'll also need to prove he can stand up against Sunday-caliber offensive linemen against the run to make it into the first round. Otherwise, he could present an excellent value in the mid-to-late second round.
Darian Thompson, FS, Boise State
Thompson received All-American recognition after picking off seven passes (he already has 14 in his career) in 2014. But the 6-foot-2, 205-pound defender isn't just a ballhawk -- he is a physical presence in the secondary and solid tackler in space and behind the line of scrimmage. Another impressive season with the Broncos will cement his status as one of the best all-around safeties in the draft class.
Nick Vannett, TE, Ohio State
Now that Jeff Heuerman is off to the NFL (2015 third-round pick of the Denver Broncos), Vannett will take the lead tight end spot in the Buckeyes' attack. He has NFL size (6-6, 260) and hands, and enough speed to do more than just move the chains if left unchecked. He even has the agility and willingness as a blocker to handle H-back duties. Look for Vannett to become a favorite target for whichever of Urban Meyer's three talented quarterbacks is running the offense in 2015.
Antwaun Woods, DT, USC
Googling the phrase "low center of gravity" should bring up a picture of Woods (6-1, 325). He missed out on the Holiday Bowl after tearing a pectoral muscle during practice, but scouts saw enough of him during his second year as a starter on the nose to know that he can be the "immovable object" to halt the "unstoppable forces" known as NFL running backs.