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How To Scout a Quarterback (Part Two): The Key Stats & The Red Flags

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NFL: Combine Brian Spurlock-USA TODAY Sports

Welcome back for Part Two on scouting a quarterback like the actual pros!

The first part of this 4-part series found here on how the Parcells Rules apply to the quarterbacks of today.

This time, we’re going to look at which stats matter for Quarterback evaluators and which ones can be indicators of red flags for prospects.

“Red Flags” here meaning “fatal flaws” or possible problems for quarterbacks, such as throwing too many interceptions or not being accurate enough, not comparing quarterbacks directly to each other, but rather to the overall benchmarks.

To clarify further, this is not the “stat box scouting” as some might believe, but are merely statistics that scouts and teams DO take into account and DO believe are important as part of the evaluation.

And without further ado, here’s the “baseline” of measurables for NFL teams at Quarterback:

  • Height (6’2)
  • Weight (215)
  • Hand size (9”)
  • Career Completion percentage (63%)
  • TD: INT Ratio (3:1)
  • Starting Percentage, or SP%-how many eligible games did they start? (72%)

These categories come straight from an actual former NFL scout from my time working for an Arena League team.

....With the one additional statistic that I added that combined several of the “starts” and “injuries” categories into one statistic.

I call it “Starting Percentage” or “SP%”.

In short it is the number of games a prospect started in college divided by the number of games they were eligible to be a starter.

Additionally—Redshirt freshman years do not count, but time missed due to injury and years sat to transfer schools do, because you weren’t able to beat out the current starter or aren’t available to play.

The ideology behind this new stat came from my boss, the former scout, who held that number of starts was a very important stat for both college AND professional scouting as it helped demonstrate the difference between:

  • Long-term starters
  • Solid starters
  • Backups
  • And oft-injured players

As Seth Cox often says on this website, “Availability is a player’s best attribute”.

And with the goal of checking these benchmarks is to try and identify and eliminate as much risk as possible. So, while one could argue “the higher the SP% the better”, the truth is that scouts wouldn’t view it that way so much as look at players who started a lot of games and were healthy doing so.

I have set a benchmark of 72% for the time being to show a high standard for starting and playing while also acknowledging possible time needed to pass a starter or incidental injuries.

What could failing these standards show us about how a team may view a prospect? Let’s take a look at an example to see.

Below are the numbers for Cardinals 2014 4th round draft pick Logan Thomas and how he measured up against the benchmarks:

Logan Thomas Breakdown

Stat Logan Thomas
Stat Logan Thomas
Height (6'2) 6'6
Weight (215) 250
Hand (9") 10 7/8
63% Completion 55.9
3:1 TD/INT 1.35
Starting % 87%

When I ran these numbers through this grid back in the summer of 2014 during my time as an Arena Football intern, all sorts of red flags popped up for Thomas.

The career completion % was very low at 56% with a high turnover ratio. For most scouts, this was a sure sign of a highly inaccurate quarterback who struggled with turnovers.

And based on Thomas’s career, he’s demonstrated that he hasn’t been able to develop further.

That said, Thomas checked the boxes all physically and played at a high enough level to start 87% of the time he was a Hokie, meaning that he did have redeeming traits which is part of why he was a fourth-round pick.

This is how scouts view these sort of statistics. Not to replace film, but rather to complete the picture and identify chinks that might be missed from the “wow” factor of a prospect.

Of course, not all of these stats will line up perfectly with every player (for example, Cam Newton failed several of these benchmarks and was a QB transfer) but, it does help expose potential “fatal flaws” and concerns as well as which guys stand out as possible long-term starting options.

So what about the other QB’s in this year’s draft? Let’s take a look:

2017 QB Statistical Breakdown

Name Height (6'2) Weight (215) Hand (9") 63% Comp. 3:1 TD/INT Starting %
Name Height (6'2) Weight (215) Hand (9") 63% Comp. 3:1 TD/INT Starting %
Brad Kaaya 6'4 215 9 3/4 60.6 2.875 97%
Chad Kelly 6'1 224 9 1/4 63.9 2.38 42%
CJ Beathard 6'2 219 9 3/8 58.1 2.1 51%
Davis Webb 6'5 229 9 1/4 61.5 2.44 48%
DeShaun Watson 6'2 221 9 3/4 67.4 2.81 82%
DeShone Kizer 6'4 233 9 7/8 60.7 2.47 65%
Jerod Evans 6'2 232 9 3/8 63.5 5.4 26%
Mitch Trubisky 6'2 222 9 1/2 67.5 5 33%
Nathan Peterman 6'4 226 9 7/8 60.1 2.76 48%
Pat Mahomes 6'2 225 9 1/4 63.5 3.2 78%
Josh Dobbs 6'4 216 9 1/4 61.5 1.82 57%

So with that fire hydrant of information out of the way, let’s pull out a few interesting tidbits and see how NFL scouts and teams would look at these statistics:

  • Outside of Chad Kelly, all of the top 10 quarterbacks in this year’s draft hit the minimum height hands and weight requirement.
  • Only 5 out of this year’s top 10 Quarterbacks hit the 63% completion threshold, which is seen as the basic baseline for accuracy in the NFL, regardless of scheme. Beathard, Kaaya, Kizer, Peterman and Webb all failed that accuracy test.
  • Even when crossing out the hurricane game for DeShone Kizer, he still came in under 62% completion, which is a red flag. When taking out the games played by Trubisky and Evans in the same storm, their completion percentages went up to 65% and 70%; however, both saw this jump from one game due to being starters for only one season. NOTE: The highest completion % is important, but because different schemes ask different levels of difficult throws, having the highest percentage doesn’t necessarily mean you are the most accurate quarterback. It’s more a box to check for scouts.
  • Chad Kelly actually hit the 63% completion mark, but also had one of the lowest touchdown: interception ratios of the group. But for comparison, Kelly’s 2.41 ratio is MILES better than a top 10 pick in Jay Cutler, who had a 1.35 ratio at Vanderbilt.
  • Only THREE quarterbacks actually hit the 3:1 Touchdown to INT ratio for their careers: Jerod Evans, Mitch Trubisky, and Patrick Mahomes. And Mahomes was the only one of that trio who was a starter for more than one season.
  • When factoring out the hurricane games they played in, Trubisky and Evans had 5:1 ratios each. But again, those numbers happened in only one year of starting. Kaaya and Watson were very close with a 2.8 to 1 ratio, but each turned the ball over enough that they didn’t pass.
  • All in all, Trubisky and Evans practically had the same year, with almost 30 TD’s, 6-7 interceptions, a low completion game in a hurricane and were a one-year starter. And yet Trubisky is the one getting top 5 love while Evans....is flying under the radar.
  • For the “Starting Percentage” or SP% statistic, Brad Kaaya started 100% of the games he had eligibility for, meaning he was the unquestioned starter from the moment he stepped on the field from tand didn’t miss a game for injury or was forced to transfer for off-field issues or lost hold of his starting job. Watson also started 82% of his games, despite playing with a torn ACL in 2014. Quite impressive for both.
  • Kaaya, Mahomes and Watson started 80% or more of the college games they were eligible to play in, passing the established 72% SP% threshold for starters.
  • Even with tearing his ACL in 2013, Watson made up for time missed by playing in four extra games in two national championship trips to check the box.
  • After Deshone Kizer at 65%, none of the other quarterbacks had a higher SP% than 51%. This likely indicates a variety of factors, including losing starting jobs and transferring (Webb, Peterman) being a backup for a while rather than starting quickly (Kizer and Trubisky) or major injury (Webb, Evans).
  • With only one season starting each, Trubisky and Evans’s SP% shows they possess a bigger risk in the draft than the quarterbacks who have more film.
  • Deshone Kizer failed the completion percentage, turnover and starting percentage tests, giving him three red flags.
  • Josh Dobbs, while measuring in well as the most athletic QB at the combine and being a solid QB failed the completion % margin and couldn’t even post a 2:1 TD-INT ratio...much less a 3:1. This won’t make him undraftable, but between the inconsistent accuracy and 30 fumbles it’s difficult to see him changing this pattern in the NFL.
  • Deshaun Watson was very consistent and only failed the threshold in one category, the 3:1 TD/INT ratio by .2 of a point, while Brad Kaaya came in under that at 2.875 in addition to having too low of accuracy.

In the end, I find it interesting that there was only one quarterback who passed every single threshold physically and with their stats.

Patrick Mahomes II.

Mahomes hit every benchmark with accuracy and had a 3.2 TD/INT ratio and started a 78% of the games he was eligible to play in, not giving up his grip on the starting QB spot after he wrested it from Webb.

What this means is that Mahomes checks the box for most scouts according to his stats and is comparatively “safer”, as there is no such thing as a truly “safe” pick. Watson is close behind him and, as we may see next week, has a possible bigger argument as his level of competition is much higher.

Indeed, the numbers doesn’t say anything about other red flags such as scheme/mechanics or the like, but it’s notable that he’s a durable player with a lot of starts who protects the football.

That is the type of player that the NFL is looking for, and it’s part of why Mahomes’ stock has risen into the first round over the last month.

—So, with baseline qualities in the “Parcells Rules” and “Important Stats” out of the way, what is the next part of quarterback scouting that the real pros look to?

The answer is in: “what’s their level of competition?”. And some numbers you’ll have expected or know, while others might surprise you.

And that’s what we’ll be discussing next time in Part Three of this series.

Thanks for reading, if you have any further questions or comments about the “Starting Percentage” or SP% statistic or otherwise, you can reach me at @blakemurphy7 on Twitter or let me know in the comments!

EDIT: Updated 4/23 adding in Josh Dobbs’ statistics