Here is how ESPN.com rates the top 13 offensive line prospects in the draft:
• OT Alex Barron (Florida State)
Vital statistics: 6 foot 7½, 318 pounds, 4.86 in the 40, 19 bench press reps.
Numbers game: Two-year regular at split-side tackle slot, mostly on the left side, and started in 24 of 25 games in his final two seasons. Began career with medical redshirt after tearing his right anterior cruciate ligament after the first four games in 2000. In 2002, was the backup to Todd Williams. Over final two seasons, he averaged eight knockdown blocks per game. In that period, never graded lower than 87 percent in blocking assignment efficiency. An Outland Trophy finalist.
Upside: Terrific athlete who has all the physical qualities you want in a left tackle. Freaky-type workout numbers in all the key drills. A guy this big isn't supposed to be this flexible, but his vertical jump and change-of-direction skills verify he can be special. Long arms and a 90-inch wingspan. When he gets his hands on a pass rusher and locks out, and keeps the kind of natural separation all great pass protectors have, the deal is sealed. Very agile, moves well laterally, can mirror pass rushers. Quick enough to get out and block at the second level.
Downside: Watch him on tape and there seems to be something, maybe a natural passion for the game, missing from his makeup. Not as tough as you want in the running game. Will struggle at times against smaller, quicker ends, and will get back on his heels and lose balance. Relies too much on natural ability, will get lazy and slide off blocks. Just doesn't dominate as consistently as he should.
The dish: Given his innate tools, should be the first lineman taken, perhaps in the top 10. People question his desire, and justifiably so, but he's just too talented not to take.
• OT Khalif Barnes (Washington)
Vital statistics: 6 foot 5¾, 305 pounds, 4.92 in the 40, 26 bench press reps.
Numbers game: Despite missing most of his senior season in 2004 after breaking his right wrist in the fifth game, logged 42 career starts. Unofficially, recorded 128 knockdown blocks in final two seasons. Began college career as a defensive lineman before moving to left offensive tackle late in his 2000 redshirt year.
Upside: Exceptionally quick feet. Moves nicely laterally, can shuffle and stay in front of a defender. Big, long frame, and can probably handle another 10-20 pounds pretty easily. Takes good angles, stays balanced and will cut off the perimeter. Plenty quick enough to recover. Has flashed some nastiness in the past.
Downside: Tends to just ride pass rushers upfield rather than redirect their charge and gets beat a little too often to the inside. A tad mechanical at times. Initial punch-out doesn't have the kind of pop he will need at the next level. Comes off the ball hard enough in the running game, but tends to lean into defenders rather than driving through them. Could use a little more strength, particularly in the lower body.
The dish: There are actually a few scouts who feel his inconsistency makes him a second-rounder, but there is no way he is going to slide that far. How come? Because there are teams that feel he is an even better prospect than Barron on the weak side.
• OT Jammal Brown (Oklahoma)
Vital statistics: 6 foot 5 7/8, 316 pounds, 5.06 in the 40, 24 bench press reps.
Numbers game: Redshirted in 2000, shared time in 2001, then started the next 39 games at right tackle over his final three Sooners seasons. Oklahoma coaches credited him with 337 knockdown blocks for his career, and he had no sacks allowed and no quarterback knockdowns permitted in 2004. Surrendered just one sack, and incurred only four penalties, in his final two seasons. Earned all-Big 12 honors each of his final two seasons and was the Outland Trophy winner for 2004. Like many of the top linemen in the '05 draft, began his career as a defensive lineman.
Upside: Arguably has more natural strength and power than any of the other top-shelf tackle prospects in the '05 pool. When he's on his game, can really stun a defender with his initial surge. Strong through the hands and shoulders. Plays with nice pad level and will sustain blocks. Made marked improvement in flexibility as a senior. Nifty enough to pull and to get downfield on screens.
Downside: Still a bit too stiff at times and will play too upright and lose momentum and surge. Doesn't always lock out, and, when he allows his mechanics to erode, lets people into his body way too easily. Sometimes a count tardy off the ball. Doesn't recover as well, or as quickly, as he will need to. Will have some mental lapses.
The dish: Naturally strong and should get more powerful as his body matures. Strictly a right tackle prospect; will be a first-rounder.
• OT/OG Marcus Johnson (Mississippi)
Vital statistics: 6 foot 6½, 321 pounds, 5.45 in the 40, 21 bench press reps.
Numbers game: Four-year starter. Started in 48 games for his career, including 45 at right guard and final three at right tackle. Named all-SEC second team for his 2004 efforts. In his final two seasons, allowed only five sacks and nine pressures. Unofficially recorded 89 knockdown blocks in 2004.
Upside: Good frame, long torso, looks like he can carry another 10-15 pounds. Active blocker with nice lateral movement. Natural arm extension allows him to get separation and cushion from defenders. Knows how to use his hands. Big enough to envelop some of the speed rushers.
Downside: Plays tall and isn't always squared up. Not particularly efficient with his footwork and looks awkward at times. Quick but not especially powerful off the ball. Could use some more muscle overall but certainly through his lower body.
The dish: Played mostly at guard in college, but might lack the natural power base and functional strength to stay inside at the NFL level. Certainly looks more like a tackle, probably on the strong side, and many teams project him to that position. A little bit of a project, but has enough raw ability that he could sneak into the first round.
• C/OG David Baas (Michigan)
Vital statistics: 6 foot 4½, 319 pounds, 5.06 in the 40, 29 bench press reps.
Numbers game: Redshirted in 2000 and made just six appearances in 2001. Then started 38 straight games, including 29 of them at left guard, over subsequent three seasons. Was moved from left guard to center after the first three games in 2004 and, despite starting only nine contests at the hub, captured the Rimington Trophy, which is awarded to the country's premier snapper. Two-time All-American and twice named to the all-Big 10 team, credited with more than 25 touchdown blocks for his career.
Upside: Powerful and explosive blocker, comes off the ball hard every time, really gets into people. Great strength through his lower body. Possesses the kind of short-area quickness you want at either guard or center. Knows and understands the angles game and, combined with terrific mechanics, plays with nice leverage and balance. A fighter and will win most of the hand battles. Won't get knocked off his feet. At this point in his career, a better run blocker than pass protector, but improving in the latter area. Superb recognition skills, good enough laterally to pick up the blitz.
Downside: Doesn't have great feet and won't always get out on the linebackers or get downfield on screens and swings. Has a habit of stopping his feet and, when he does that, he gets stymied and struggles to disengage. Played too heavy the first half of his senior year and looked sluggish until he shed some weight. There are occasions when he will let his emotions get the better of him.
The dish: In a league where center is suddenly emerging as a priority position, could be the best of a deep bunch of snappers even though he hasn't been much exposed to the position. Tough-minded, savvy player who could anchor a team's middle for a lot of years and will probably be chosen in the second round.
• OT Adam Terry (Syracuse)
Vital statistics: 6 foot 8, 330 pounds, 5.40 in the 40, 21 bench press reps.
Numbers game: Sat out 2000 season as a redshirt, then played as a backup in four games in 2001. Moved into the starting lineup in 2002, at left tackle, and made 38 starts there over his final three seasons. Missed two games in 2004 because of injuries. In his final two seasons, consistently graded at over 90 percent on assignment efficiency and had 17 touchdown blocks while surrendering just four sacks. Named to the all-Big East team for 2004.
Upside: Looks like Herman Munster in shoulder pads. In fact, even at 330 pounds, looks kind of thin. Surprisingly good knee bender for such a tall player and deceptively agile. Tough enough to anchor and quick enough to seal. Smart and aware and, when he gets riled up, will flash a nasty streak.
Downside: Needs more functional strength and has to learn to play with a better base, as well. Plays narrow and will get moved around. Not real bulky. Doesn't recover well and will get beat too often straight up the field.
The dish: Intriguing left tackle prospect who might never have the foot quickness to stand out at the position but who is a hard worker and worth a second-round investment.
• C Chris Spencer (Mississippi)
Vital statistics: 6 foot 2 7/8, 309 pounds, 5.21 in the 40, 26 bench press reps.
Numbers game: A full-time starter for just one year, opened in all 11 games at center in 2004, after serving as a backup at guard and center most of career. Moved permanently to center late in the 2003 season. In 2004, coaches credited him with seven touchdown blocks and 77 knockdown blocks and allowing just one sack.
Upside: Absolutely explodes out of his stance and can knock defenders back with his initial sustained surge. Impressive combination of power, speed, quickness and technique. Can really pop people and is rarely tardy with his hands. Moves well enough laterally to pick up blitzes and seems to have enough speed to trap and pull and get out in front of the screens. Has gotten better every year and will continue to mature.
Downside: Lack of experience seems to be the only negative. There are probably some recognition skills he will have to polish.
The dish: Regarded as one of the premier center prospects of the last 10 years or so. The increase in 3-4 fronts around the league will enhance his value, and it will be interesting to see how high an investment a team makes in him.
• OG Logan Mankins (Fresno State)
Vital statistics: 6 foot 4 1/8, 307 pounds, 5.06 in the 40, 21 bench press reps.
Numbers game: Played linebacker and tight end in high school and was a walk-on during his 2000 redshirt season. Moved into starting lineup at left tackle the next year and was a fixture there except for 2003, when he missed the entire campaign after he tore his right anterior cruciate ligament before the season began. Surrendered no sacks and no pressures as a senior and graded over 90 percent on blocking efficiency for the entire season. Was voted team's most valuable player his senior year.
Upside: One tough hombre and a classic, road-grader type of blocker. Huge hands, powerful through the forearms, strong enough to just rag-doll defenders at the college level. Relishes trench battles, just a mean guy, the kind you want mashing defensive linemen inside. Plays with a strong power base, really gets his backside and hips rolling forward and performs with impressive momentum.
Downside: Will struggle to hold the outside, so seems to project more to guard despite having played left tackle in college. Not a great athlete. Sometimes allows his mauler image to go to his head.
The dish: Gritty, blue-collar guy who will definitely be a first-day selection. All football player, a self-made success story, and no one will have to show him the way to the weight room, that's for sure.
• OG Evan Mathis (Alabama)
Vital statistics: 6 foot 5¼, 304 pounds, 4.92 in the 40, 35 bench press reps.
Numbers game: Finished his career with 47 consecutive starts and was certainly a model of perseverance. Played every game in 2002 despite fracturing his leg in spring practice that year. Fought through stress fractures in both legs to start every contest in 2003. Was named to the all-SEC team in 2004.
Upside: Remarkable in his lack of remarkability. Has made strides every season and has really demonstrated improvement over the past 12 months. Just a down-and-dirty player, a lunch-pail sort of guy whose athleticism seems to be a tad underestimated. Has nice recovery skills and change of direction, can pull and trap, seems to be able to anchor against defenders who just want to go toe-to-toe with him.
Downside: Needs to add some more strength and bulk. Plays hard but not powerfully and won't knock folks off the ball on a consistent basis. Might have to play in a zone-block scheme to be successful at the next level.
The dish: The arrow is pointing up. Scouts love his work ethic and like the steady progress he seems to make from one season to the next.
• OT Chris Colmer (North Carolina State)
Vital statistics: 6 foot 5¼, 306 pounds, 5.22 in the 40, 29 bench press reps.
Numbers game: Granted an unusual sixth season of eligibility after he missed the entire 2003 campaign because of Parsonage Turner syndrome, a rare viral infection that caused numbness in his left shoulder. Appeared in 47 games for his career. Finished with 288 knockdown blocks.
Upside: Aggressive and explosive, a battler who plays every snap hard, will go right to the whistle. Solidly built. Has the ability to sustain a block and drive a defender off the ball. Smart, tough, very aware player.
Downside: Medical dossier is a thick one and certain to draw red flags. In addition to the Parsonage Turner syndrome, had shoulder and ankle surgeries. Doesn't have great feet and not very athletic. Pretty much locked in as a right tackle candidate.
The dish: You've got to love his tenacity and perseverance, but the medical file is going to scare off some teams, and you can't blame them.
• OT Ray Willis (Florida State)
Vital statistics: 6 foot 5 5/8, 327 pounds, 5.15 in the 40, 27 bench press reps.
Numbers game: Gained early starting experience as redshirt freshman in 2001 with two opening assignments. Except for missing two games to a foot injury in 2002, started for next three seasons at the "tight tackle" position, which essentially is on the strong side. Graded out at 81.9 percent for his career and allowed just nine sacks. Finished with 35 career starts.
Upside: Muscular build and well defined. Thick and barrel-chested, with big shoulders and long arms. Knows how to use natural strength to steer defenders. Strong techniques, knows the game, understands nuances of leverage and mechanics. Uses his hands well. Incredible effort, plays right up to the whistle on every snap. Married and very mature. Willing to go the extra mile.
Downside: Despite initial quickness, doesn't always sustain his power and will quit moving his feet at times. Doesn't exactly explode into defenders and won't finish off all his blocks. Has had some shoulder problems in the past. Lack of foot speed means he is pretty much locked in to playing the right side.
The dish: Scouts love him because, essentially, what you see is what you get. The kind of player you want to draft and nurture because he has such desire that he'll naturally improve with good coaching. Nothing remarkable about him, but a blue-collar plugger will be a coach's dream. Will go a little higher than people think.
• OG Elton Brown (Virginia)
Vital statistics: 6 foot 4 7/8, 329 pounds, 5.55 in the 40, 19 bench press reps.
Numbers game: Started four games in 2001, first true freshman to start on Cavaliers' offensive line in more than 30 years. Played principally at right guard early in career, then moved to tackle. Surrendered only three sacks in his career, none in 2004, and had 76 knockdown blocks last season. Finished his career with 35 straight starts. Team captain in 2004, when he earned all-ACC honors.
Upside: Huge, girthy body, tough guy to get around. Thick all through the upper body but surprisingly thin hips and thighs. Can control the inside gaps with his raw size. Powerful man and can jolt defenders. Strong drive-blocker. Good recovery and redirection skills.
Downside: Gets lazy, loses focus on mechanics and plays stiff. Doesn't bend his knees. Allows himself to get pushed around too much. Needs more muscle definition.
The dish: Probably the best pure guard skills in the draft, but on a slippery slope. Begged off the Senior Bowl game because of an injury, didn't work at the scouting combine, then cramped up at his pro day workout and couldn't finish all the drills. Some scouts are just flat-out disgusted with him. On ability, a second-rounder, but could slide because people question his desire and attitude.
• C Jason Brown (North Carolina)
Vital statistics: 6 foot 2¾, 313 pounds, 5.40 in the 40, 23 bench press reps.
Numbers game: Played as a true freshman in 2001, appearing at tackle, his high school position, in eight games. Moved to center as a sophomore and compiled a streak of 38 straight starts in the middle. Allowed zero sacks, according to Tar Heels coaches, over the final three seasons of his career. Consistently graded out at more than 90 percent in '04 and established an unofficial school record with 15 knockdown blocks in one game and 142 for the season. Named a captain for his senior season.
Upside: Has the kind of massive trunk and legs you want at the position. Plays under control, in balance, and with a consistent power base. When he sinks his hips, he's next to impossible to move, and he can flat-out stop people in place. Comes off the ball hard, with a purpose, and locks onto defenders and doesn't let go. Quick and powerful hands, can redirect defenders, and frustrate them. Determined. Wants to be special. Never missed a practice in four years. Nice football sense and very bright off the field, too.
Downside: Doesn't have great feet and will struggle versus quickness. Tends to reach a little and overextend. Weight got out of control earlier in career, and he had to lose about 25 pounds before his senior season.
The dish: Some teams wish he were an inch or two taller, but everyone loves his character and work ethic. Could go off the board in the second round.
Len Pasquarelli is a senior writer for ESPN.com.