2013 Combine O-Line Tale Of The Tape: Making Sense Of The Numbers

The first step in assessing Combine performance is to look at the raw numbers from the position drills. Sure, running 40 yards in a straight line doesn't tell you all that much about how a guy can play football, but when teams look at rookie prospects, one of the first things they look at is whether the player meets the physical prototype expected from the position.

Bill Parcells explained the rationale for this quite succinctly in a TV interview last year: For every position, there is a certain combination of physical measurables that has proven successful in the NFL, and deviating from this success model doesn't have high chances of success.

So the first step in looking at the numbers for the offensive linemen is to understand what NFL teams are looking for. A while ago, Gil Brandt published a set of target test results for Combine measurements. Here are the numbers for the interior linemen.

Overall, not much of a difference between the two positions, but the small differences in the numbers show that tackles need to be a little faster, while guards and centers have to be quicker and stronger.

Not much math involved in this assessment, as we'll simply sum up the number of target measurements a prospect meets. You'll usually only have a handful of prospects who meet every single target, and teams vary in the importance they place on each measurement, but the less of these targets a prospects hits, the less attractive he becomes to NFL teams.

The next table shows all the basic measurements for the offensive linemen at the Combine. By default, the list is sorted by the 'Targets Met' column at the very right which provides a tally of how many of the seven target measurements a prospect was able to meet. For your convenience, the table is sortable, so you can sort and re-sort to yor heart's delight. "Rank" indicates where a player is currently ranked on the CBSSports big board.

Offensive Linemen, 2013 Combine measurables (click column header to sort)

That's a lot of numbers to look at. But if you only focus on the "Targets met" column on the far right, you'll see the players that match the NFL prototype for the position - or not. You've got to like guys who hit five or more of the target measurements, and you've got to wonder about the guys who hit less.

Case in point: Luke Joekel, despite participating in all drills, only met three targets, while fellow top tackle prospects Eric Fisher and Lane Johnson ticked off six out of seven boxes. Joekel may not be a lock to be the top tackle taken anymore. Of course, Joekel still has his Pro Day to correct the Combine numbers, and there's always game tape. Overall though, being successful in the NFL is about more than simply ticking the right boxes, so let's look at a couple of different metrics to better understand the Combine performance.

1. Kirwan Explosion Index: [BENCH PRESS REPS + VERTICAL JUMP + BROAD JUMP = EXPLOSION NUMBER]

First proposed by Pat Kirwan, this is a simple addition that adds up the number of bench press reps with the broad and vertical jump values. Technically, you can't just add reps, inches and feet into one aggregate number, but so be it.

What this number gives you is an idea of the explosive strength of a lineman. An explosion number over 70 is considered a very good result. But since only five prospects exceeded 70, we'll make an allowance for this draft class and assume that anything above 65 is still good.

2. Explosive Power: (VERT+3.5*BROAD)*(WEIGHT/HEIGHT)/3000

This is a metric that was developed, as far as I know, by Tony Wiltshire, a writer for BuffaloBillsDraft.com. Where about half of Kirwan's Explosion Index (KEI) is made up of upper body strength, the Explosive Power metric focuses on lower body strength relative to a player's physique.

This metric gives you a good idea of how strong a lineman is off the snap and the amount of pure physical force he can generate out of his legs. If you think of the KEI as horsepower, then think of the Explosive power metric as torque. A value over 1.05 is elite, a value over 1.0 is excellent, and anything over 0.95 is still very good.

3. Lateral Agility: [40-YARD DASH TIME - 20-YARD SHUTTLE = LATERAL AGILITY]

This number uses the differential between the 40-yard dash time and the 20-yard shuttle to get a better feel for the lateral agility of a player, as the differential provides information beyond simple long speed and short-area quickness. Generally speaking, a player who notches a .50 or better is considered to have outstanding lateral agility, a quality highly sought after in interior linemen who usually operate in very tight spaces.

4. Speed Score: [(WEIGHT * 200) / (40-TIME ^ 4) = SPEED SCORE]

Not all players are created equal, and it doesn't make a lot of sense comparing 40-times of players who may have a weight difference of 60 pounds. The Speed Score takes into account both a player's time in the 40-yard dash as well as his weight.

The ratio was initially developed for running backs, but works just as well for linemen. The multiplications look complicated but actually give each measurement roughly equal weight and ensure that an average score (for running backs) comes out at about 100. The higher the resulting number, the better the combination of size and speed in a player. A good score for an offensive lineman is 90 or higher.

The formula also allows us to put the 40-times of Terron Armstead (306 pounds, 4.71 forty) and Lane Johnson (303, 4.72) in perspective. Their pound-for-pound speed would be the equivalent of a 200-pound RB running a 4.235 (Armstead) or 4.254 (Johnson) forty time. Mind boggling.

The table below summarizes the four sets of figures above for the 2013 linemen. The figures in bold show where a prospect exceeded the figures outlined above, the column on the far right shows how many of the four targets a prospect exceeded.

Offensive Linemen, 2013 Combine additional metrics (click column header to sort)

These numbers are by no means a definitive assessment of how good a given prospect is. They are just one of the many pieces of information that teams put together to assess and grade a prospect. Last year, the only two interior offensive linemen (I didn't do the calculation for tackles last year) to beat all four metrics were David DeCastro and Kevin Zeitler, and it's no coincidence the two were the top two guards drafted, with the 24th and 27th pick respectively. Here are a couple of observations about this year's draft class:

1. Based on his Combine performance, Eric Fisher is the best tackle in this year's draft class. Some people might argue that Joekel's game film trumps Fisher's, and that may well be true, but if I had to put money down on who I thought would have the smoother transition to the NFL, I'd put it on Fisher. I'd also put money on Jonathan Cooper and Brian Schwenke.

2. Chance Warmack, D.J. Fluker and Larry Warford have been popular names in Cowboys Nation, but I'd move them down on my big board. Sure, you'll hear arguments about how a player plays much more powerful than he showed at the Combine, or that a guy may not have run fast but has really quick feet, perhaps you'll hear how a guy has a phenomel reacton time that doesn't show up in the Combine drills. That may all be true. But would you bet your first or second round pick on it?

3. I'll take the ripped guy over the fat guy any day of the week and twice on Sunday. Our own Tyron Smith is the prototype of what a modern offensive lineman looks like. Some interesting players in the same mold who put up very strong numbers are Terron Armstead, David Quessenberry, Kyle Long, Vince Painter or Reid Fragel.

4. The latter are intriguing under-the-radar prospects: Reid Fragel played tight end at Ohio State through his junior season and only converted to OT as a true senior. The almost completely unkown Vince Painter has a 4th-5th round grade, according to our resident scout Birddog26:

Painter is a former DT who converted to RG his sophmore season and then to OT his junior season. He has been an outstanding special teams player who was just named starter on the Oline this season. He is still very raw with his technique and mechanics and will need time to develop on the Oline but can come in and contribute on ST right away. He is an Alex Albright/Jeremy Parnell type prospect who shows great athleticism but will take a couple of years to really see what you have in him.