Follow Up on QB Fragility

Follow Up on QB Fragility

Submitted by MCalibur on August 6th, 2009 at 11:07 PM

After reading the reactions to the first diary I wrote on the issue of QB injury rates, I thought it’d be worthwhile to go back and address some of the skepticism still lingering.  For the most part, the source of the skepticism was in regards to the number and scope of the data points or in how the QBs were split into their Threat Level categories.

More Data Please

Addressing the first issue was straightforward—get more data. I included the 2004-2007 seasons for a total of 5 seasons including 2008. The scope was all FBS schools and all starting QBs with starters defined as players who averaged more than 17 plays (passes + runs) per game they played in. This level of play was chosen based on the median of the data in that category. One tweak I added was to increase the resolution of the data to include partial games (ie. if a QB gets knocked out in the 3rd quarter and missed the next two games, I counted 2.25 games against him). I also corrected a few errors I found along the way.

Cherry Picking

The issue of the chosen break points was simply a matter of choosing one arbitrary line in the sand over another, I went with the one I thought made the most football sense. I actually considered using the quartiles of the data as break points to ensure that there would be equal numbers of QBs in each category. But, we know that this simply isn’t the case—there are way more Jimmy Clausen/Mark Sanchez/Matt Staffords (Threat Level 0) than there are Pat White/Terrell Pryor/Tim Tebows (Threat Level 3).  

The goal of using categories was to group similar players together in an unbiased way. Using whole number denominators (1 run per 2 passes, 3 passes, etc) was a reasonable football-sense based method to do this. Using quartiles would have put the level 3 split data at 2.78 passes per run…huh? Ok so maybe you round up to three then but a) how is that not arbitrary and b) does it make sense to put Steven Threet into the same category as White/Pryor/Tebow? Obviously not…

Regardless of all that, the expanded dataset neutralizes this concern

The Goods

Anyway after all the grunt work was done, not much changed but the extra data does yield more insight. The average injury rate for all QBs was 23.6%. Level 3 running threats came in at a 25.3% rate and level 0 threats were injured at a 23.9 % clip. I’ve left my hypothesis testing skills mercifully nestled amongst the dust and cobwebs of my mind but there’s no statistically significant difference here. The theory that option QBs are more likely to get injured than the average QB is a load of crap.

There does seem to be a significant deviation from the norm in the injury rates of level 1 and level 2 QBs, with 1’s getting injured at a lower than average rate and 2’s getting injured at an above average rate. A possible explanation for this is that Threat level 1 QBs enjoy the safety of the pocket but also have the ability to escape from pressure and not be sitting ducks like threat level 0 QBs. On the other end of the injury spectrum, level 2 QBs leave the pocket but don’t have the speed/agility/field vision/down field linemen necessary to elude defender’s looking to teach them a lesson. This is definitely an eye opener. If you’re going to ask your guy to be a running threat on a regular basis, he had better be a slippery one and you’d better have blockers on the second level. Check and check.

The last interesting note is that 1 out 4 teams can expect to lose a QB for about 3 games; that’s 3 teams each from the B10, SEC, ACC, etc. I would have never guessed that. Another way to look at it is that a recruit can/should be expected to miss 3 games over a 4-year college career.... yikes. Having at least 2 game ready backups is an absolute must, regardless of offensive system.

Threat Level

No. of QBs

Injured QBs

Lost GMs
(% of Total)

Avg. Games Lost

QB Inj %

2008

3

26

6

7.5%

3.08

23.1%

2

24

10

7.7%

2.33

41.7%

1

46

11

9.2%

4.89

23.9%

0

64

14

4.8%

2.79

21.9%

2007

3

19

7

7.3%

2.5

36.8%

2

26

7

5.5%

2.57

26.9%

1

35

7

6.5%

4.04

20.0%

0

79

19

6.9%

3.61

24.1%

2006

3

14

4

7.4%

3.19

28.6%

2

34

13

10.4%

3.38

38.2%

1

36

4

4.6%

5.31

11.1%

0

60

13

5.1%

2.96

21.7%

2005

3

19

4

5.5%

3.00

21.1%

2

29

8

8.5%

3.47

27.6%

1

36

6

3.0%

2.08

16.7%

0

60

16

6.2%

2.72

26.7%

2004

3

17

3

3.6%

2.33

17.6%

2

28

4

1.6%

1.25

14.3%

1

40

6

3.5%

2.67

15.0%

0

63

16

7.4%

3.39

25.4%

All Seasons

3

95

24

6.3%

2.81

25.3%

2

141

42

6.9%

2.81

29.8%

1

193

34

5.6%

3.88

17.6%

0

326

78

6.1%

3.13

23.9%

All

755

178

6.1%

3.3

23.6%

Brace for Impact

Given the rhetorical skill of most of the visitors of this site, I’ll take a second to put out a preemptive strike against the “how do we know Tate/Denard/Devon wont be a level 2 Threat?” argument. Simply put, we don’t. But, the categories aren’t an explicit evaluation of the athleticism of the player; they only allow us to infer his physical skills by how he’s deployed by the coaching staff. 

Example. Juice Williams ended up as a marginal level 2 QB in 2008 with an R/P ratio of 0.46. The previous 2 seasons he qualified for level 3 status which is not a surprise. His skills didn’t diminish and the offensive scheme of the Illini did not change but for whatever reason, he ran a few time less than before and ended up in the upper end of the same category as Steven Threet. Actually, he ran more often (+2 runs per game ’07 v. ‘08) but passed a lot more (+11 passes per game). 

Now on the flipside, does anyone believe that Threet would have had a better chance of staying healthy if we had run him more? The point is that the athleticism of the QB determines his injury risk outside of the pocket, not the number of excursions outside of the pocket he makes.

Busting The Myth of Option QB Fragility

Busting The Myth of Option QB Fragility

Submitted by MCalibur on July 27th, 2009 at 12:14 AM

One of the criticisms often heard of the spread option is that the QB in the system gets hurt with a higher frequency due to how many hits he takes. The idea does seem to make sense but does it hold up to reality? I’ve searched the MGOBLOG archives and haven’t seen a specific discussion of the topic so hopefully I’m presenting some new material. 

The first thing to decide is an objective method with which to classify QBs without cherry picking players. To do this I generated a run-to-pass ratio by dividing total rushes by total passes. A high number means the QB runs a lot; a low number means he’s John Navarre. I then needed to decide on thresholds for running QBs vs. pocket QBs. After screwing around with the numbers for a while I came up with a Threat Level rating—not to be mistaken with Threet Level rating. 

An R/P ratio of 0.5 or higher (1 run for every 2 passes) was a level 3 threat to run, 0.33 to 0.5 (1 run for every 3 passes) was level 2, 0.20 to 0.33 (1 run for every 5 passes) was level 1, and less than 0.2 is a level 0 threat to run. I admit these thresholds are somewhat arbitrary but they hold up to sense checks. Here are some notable QBs in each category from 2008:

Level 3—Dual Threat QB: Pat White – West Virginia, Tim Tebow – Florida, Terrelle Pryor – Ohio St.

Level 2—Running QB: Juice Williams – Illinois, Kellen Lewis – Indiana, Steven Threet – Michigan

Level 1—Mobile QB: Colt McCoy – Texas, Nick Sheridan – Michigan, Daryll Clark – Penn St.

Level 0—Pocket QB: Graham Harrell – Texas Tech, Sam Bradford – Oklahoma, Chase Daniel –Missouri, Mark Sanchez – So. Cal, Jimmy Clausen –Notre Dame, Brian Hoyer –Michigan St.

The next order of business was to filter out irrelevant players. To do this, I assumed that a QB needed to register at least 17 plays (any combination of passes and rushes) per game he played in to qualify as a non-scrub QB.

Then came the hard part: tallying the number of injured QBs in each category and the number of games lost due to injury then determining if there is indeed a difference between the four running threat levels. According to critics of the spread option, level 0 QBs should get injured the least often and level 3 QBs should get injured the most often. After a few solitary hours and a couple of six packs here’s what I found.

Threat Level

No. of QBs

QB Injury %

% Games Lost

Avg. No. of Games Lost

26

23.1

6.1

2.5

2

24

41.7

6.6

2.0

1

46

23.9

10.8

5.7

0

64

21.9

5.7

3.3

Surprise, surprise the critics are wrong. On a percentage basis the only group that suffered an out of norm injury percentage were level 2 QBs which I think of as QBs that are used like running backs (Juice Wiliams) or QBs that are too slow to be running in the first place (Steven Threet). All other groups suffered injuries at about a 23% clip. Meaning about 1 out of every 4 QBs in a given category lost playing time due to injury in 2008.

An interesting note that I did not expect to see is in the Average Number of Games Lost Column. Apparently the more stationary you are the more serious the injury you will sustain. This makes sense; in the pocket 10 linemen weighing about 300 lbs each surround the QB. In space, he can slide or go out of bounds and if he does get hit it’s by a 230-pound linebacker or a 200-pound defensive back.