guest column by Gregor Bozic

For many years, the popular belief among NFL analysts was that the success of an NFL team comes with a quarterback who can stand tall in the pocket and deliver the ball downfield. Members of the elite group of active quarterbacks, Peyton Manning, Tom Brady and Drew Brees, for instance, also earned their reputation by making plays almost exclusively from the pocket.

But there is a growing group of young signal-callers who can make plays with their legs, scrambling to escape the pressure or using their legs on an occasional designed run play. Russell Wilson, Colin Kaepernick and Cam Newton are three of the players considered dual-threat quarterbacks who entered the league in recent years and have already had their share of success. Consequently, we now hear from the analysts that the ability to extend plays and make something out of nothing is the most vital component of the art of the NFL quarterbacking.

In an attempt to graphically present the well-known difference between classic pocket passers and athletic quarterbacks capable of improvising, I've designed visualizations based on collected spatial data for three active NFL quarterbacks. In this article, the group of pocket passers will be represented by Peyton Manning. Wilson and Kaepernick will represent the group of mobile quarterbacks.

I divided the backfield into a grid of so-called "throwing cells." I reviewed the games and charted the locations from where the quarterbacks threw passes or took a sack during 2013 playoffs and mapped them out in the pre-defined grid. In addition to "coordinates," I've collected "attribute" data to determine pocket/out-of-pocket throws and sacks, behind the line of scrimmage passes, designed rollouts, and passes thrown under pressure. All of which helped me further analyze spatial-based data for Manning, Wilson and Kaepernick.

The first visualizations are known as heat charts. The charts will answer two questions; from where and how often did the trio of quarterbacks attempt a pass in a certain area of the backfield? I grouped pass attempts into classes based on number of attempts which fall into regular hexagons with a side length of one yard.

Russell Wilson attempted just 68 passes in Seattle's three playoff games. Wilson completed 43 of them for 524 yards with three touchdowns. Of the 68 attempts, Wilson threw 13 passes behind the line of scrimmage, which is 19.1 percent and presents the highest rate of all three players considered in this article.

We can see from the chart above that Wilson most frequently (seven times) attempted a pass 7-to-8 yards deep in the backfield, just inside of the right hashmark. The spots where Wilson threw a pass in the playoffs are scattered all around the backfield. Still, the vast majority of passes were attempted from the right side of the field. On average, Wilson tossed a pass when located seven-and-a-half yards behind the line of scrimmage.

Next is the heat chart of Kaepernick's pass attempts. Kaepernick attempted 82 passes in three games during the 49ers' 2013 playoff run. He completed only 45 passes for 576 yards with three touchdowns and three interceptions. One of the differences compared to Wilson is the number of passes which didn't travel past the line of scrimmage and are thus not shown on the chart. Kaepernick attempted just three passes, or 3.7 percent of the total.

Just like Wilson, Kaepernick most frequently (nine times) attempted a pass 7-to-8 yards deep in the backfield. Here too we can see passes attempted from all over the backfield, but Kaepernick was more willing to pull the trigger while rolling to his left. On average Kaepernick attempted a pass eight yards deep in the backfield.

A completely different picture shows up in Manning's heat chart. Manning threw 128 passes during three playoff games, which is almost as much as Wilson and Kaepernick combined (150). The ultimate pocket passer completed 71.1 percent of his passes and gained 910 passing yards with five touchdowns and three interceptions. Eighteen of his passes, or 14.1 percent of the total, didn't make it past the line of scrimmage. Unlike the two mobile quarterbacks, Manning was able to make subtle movements and climb up the pocket to avoid the pressure. He often released the ball quickly from the spot where he waited for the ball to be snapped, without further dropping back behind the line of scrimmage.

As a result, spots from where Manning threw passes are much more condensed and closer to the line of scrimmage, with an average "throwing" line at six-and-a-half yards behind the line of scrimmage. The quarterback of the Denver Broncos most frequently (20 times) threw a pass just inside the right hashmark, 5-to-7 yards deep in the backfield.

The heat charts reveal the main difference in throwing tendencies, in terms of throwing locations, of Manning, Wilson and Kaepernick. The spot where the center snaps the ball is dependent on the result of the previous play. So besides the obvious out-of-pocket attempts, the ones closer to the sidelines, we can't see how many of the passes were actually thrown outside the boundaries of the pocket. To answer that I've designed another chart with only pass attempts thrown outside the tackle box. All three quarterbacks are in one chart here.

There's no doubt Manning prefers playing from the pocket and it showed during 2013 playoffs in which he threw only five out-of-pocket passes in 128 attempts. Three of those five were on designed rollouts, including a one-yard touchdown pass thrown against the New England Patriots in the divisional round. Overall, Manning went 4-of-5 for just 21 yards and one touchdown on those attempts. Wilson and Kaepernick combined for 37 out-of-pocket passes, almost one-quarter of their combined 150 attempts. Kaepernick was extremely successful on the move. He completed 12-of-20 attempts for 141 yards and two touchdowns. Only seven of those 20 attempts came on a designed rollout, all seven to the right side. Wilson did not throw a touchdown pass when working outside the pocket, but he did gain 165 yards with a 58.8 completion percentage. 6-of-17 attempts were on designed rollout plays, with only one to the left side.

The charts shown so far only include pass attempts and ignore scrambles and sacks. But we know those are pass plays by design. The ability to escape the pressure and avoid the sack is a skill attributed by many to the group of mobile quarterbacks. But the fact is that good pocket passers take far less negative plays and have lower sack rates. Manning never scrambled and took only one sack during the 2013 postseason. His pocket presence and ability to process information pre- and post-snap allowed him to release the ball quickly and avoid those kind of negative plays. Manning's total pass plays count is at 129, if we take into consideration pass attempts, scrambles and sacks, which gives him an 0.8 percent sack rate.

Wilson and Kaepernick, considered as two of the best mobile quarterbacks, absorbed far more negative plays. Kaepernick is generally quick to leave the pocket and sometimes it’s hard to identify whether he actually scrambled or ran a designed draw. Based on my game charting he scrambled seven times, took six sacks, and finished the postseason with a sack rate of 6.3 percent. Of the three quarterbacks, Wilson was the one that was pressured the most and he too tends to leave the pocket early when he feels the pressure and turns himself into runner. He finished with the highest sack rate, with 68 pass attempts, six scrambles and seven sacks. Wilson recorded a 8.6 percent sack rate. In the next image we will see the locations of the sacks the quarterbacks took during 2013 playoffs, further broken down with relation to the pocket.

The lone sack Manning took was a strip sack late in the Super Bowl which happened within the pocket. Four of Wilson's seven sacks occurred close to the line of scrimmage. On one occasion he scrambled and ran out-of-bounds just shy of crossing the line of scrimmage, and three times he scrambled and dived for a minimum loss of yards. Three of six total Kaepernick sacks took place when he was working outside the pocket. Similar to Wilson he took one sack when he scrambled to the left and ran out-of-bounds just short of reaching the line of scrimmage.

The visualizations presented in this article are based on small-sample sizes of spatial-based data. Despite that we are still able to see that each of the players display certain tendencies when playing the most important position in the game of american football. The differences between the two types of quarterbacks can clearly be seen on the charts. Peyton Manning, who has great pocket presence, rarely leaves the pocket. Even under heavy pressure when facing the No. 1 defense in last season's Super Bowl, Manning took only one sack and left the pocket only twice on 49 pass attempts, both times on designed rollouts.

Wilson and Kaepernick leave the pocket while under pressure, trying to make big plays on the move. With those big play chances also come an increased rate of negative plays. As right-handed quarterbacks they are inclined to roll out to the right, as was the case during 2013 playoffs. But as the postseason sack chart revealed, those outside pocket sacks all happened on the left side of the field. When rolling to his left it is much more difficult for a right-handed quarterback to be accurate with his throws and get rid of the ball on time to avoid negative plays.

It is important to remember that a quarterback's performance isn't only a function of his own skills. The trio of quarterbacks operated in different kind of offenses behind different offensive lines. Helped a great deal by their defenses and power running game on offense, both dynamic quarterbacks weren't asked to do a lot in the passing game. Kaepernick, for example, attempted only five passes in the first half of the 2013 NFC Championship Game. The 49ers game planned to use him more as a running threat against Seattle's top-rated pass defense. Wilson, who played behind a porous offensive line, handed the ball off to Marshawn Lynch 50 times and only attempted 43 passes in the Divisional and Championship Game combined. That's less than Manning's attempts total in Super Bowl XLVIII alone.

With a larger sample size of the data we could perform spatial analysis and look for quarterbacks' tendencies when playing against certain defenses. Kaepernick's heat chart when facing teams from the NFC West would certainly look different than a chart which would include data for the rest of the 49ers' 2013 regular season opponents. With visualizations designed based on data splits for opponents or field position, we would be able to further explain and evaluate space-dependent performance of the quarterbacks.

Gregor Bozic is a geodetic engineer living and working in Slovenia, a beautiful country on the sunny side of the Alps, and a fan of the San Francisco 49ers since 1988.