Analyzing Rookie Quarterback Progression
About a year and a half ago, I sat down and did a comparison of rookie and veteran quarterbacks. My goal was to determine how rookies fared in certain statistical categories, as related to their veteran counterparts. There were a few surprises (rookies actually rely on their tight end less than veterans) and many revelations we would’ve expected (worse completion rates, higher interception rates for rookies).
With two more seasons of PFF data available, I wanted to dig deeper into the rookie vs. veteran discussion. Today, I’ll be comparing the numbers of quarterbacks who played significant rookie-season snaps to their career marks.
There’s a lot I need to explain about our first chart before we begin the analysis. First of all, there are 11 quarterbacks shown. The first row of data you see for each player is his rookie-season production. The second row is his stats the very next season. A third row is shown for any player drafted before 2011, which is a total of all post-rookie season stats.
Key: ‘DB’ = Dropbacks. ‘aC%’ = (Completions+Drops)/Aimed Throws. ‘YPAim’ = ‘Yards Per Aimed Throws’. ‘aDOT’ = Average depth of target. ‘NA%’ = Percentage of pass attempts that are not aimed (batted balls, spikes, throw aways, balls disrupted by a quarterback hit’). ‘Scr%’ = percentage of dropbacks resulting in a scramble. ‘INT%’ = Interception rate. ‘Sack%’ = Sack rate.
Okay, now we can analyze.
Working our way through the chart on a category-by-category basis, we see some clear trends. The most noticeable is in the interception department. Note than 100 percent of the seven quarterbacks drafted prior to 2011 improved their interception rate after their rookie season. Of all 11 quarterbacks, only two (or 18 percent), Matt Ryan and Andy Dalton, had a worse rate during their sophomore season.
Another interesting category is that of scramble rate. Of our seven (we’ll call them “experienced”) quarterbacks, all but one (or 14 percent), Colt McCoy, scrambled less often after their rookie season. Most of the names on our list are pocket quarterbacks, so it’s interesting that even these non-scrambling signal callers tend to abort the pocket less often as they gain experience.
Next, it’s worth taking a look at yards-per-aimed throw, which is really just a better version of the popular yards-per-attempt. Interestingly, only six of our 11 quarterbacks (or 55 percent) had a higher YPA in their sophomore season. I would’ve expected a higher rate there, but based on what we see in other categories, experience seems to lead to more conservative play. Of our seven experienced quarterbacks, only four (57 percent) improved their YPA after their rookie season.
The final category that really jumps off the page is the non-aimed pass rate. Of the seven experienced quarterbacks on our list, six have a lower rate from their sophomore season on. Why is this important? The way I look at it, non-aimed throws are basically wasted throws. The quarterback drops back, usually with the intention of completing a pass, but when a non-aimed throw comes into play, there is zero chance for the ball to be caught. A quarterback can’t always control this category (spikes depend on game flow, for example), but it’s clear that they do find a way to keep the wasted throws (throw aways, batted balls, hit disruptions) down.
Focusing only on rookie-to-sophomore year changes, we see a better completion rate in 8-of-11 (73 percent) instances, a lower average depth of target in 7-of-11 (64 percent) cases, and a lower sack rate in 8-of-11 (73 percent) instances.
I touched on it briefly earlier, but here is what we’ve learned so far. Rookie quarterbacks average deeper throws, complete fewer passes, “waste” more throws, scramble more often, throw more interceptions, and are more likely to be sacked. It makes sense. As quarterbacks become more experienced, they rely on safer, shorter throws rather than aborting the pocket in order to scramble, or find an open receiver, which sometimes leads to additional throw aways and hits. The safer, shorter throws lead to more completions, but fewer yards and turnovers.
In part two of our feature, we’ll take a look at pass distribution based on where the target lined up on the field.
Key: Back = Player lined up in the backfield. Wide = Player lined up out wide, not including the slot. Slot = Players lined up in the slot. In Line = Players lined up on the line. This usually will only include tight ends.
Although this chart proves useful on a quarterback-to-quarterback basis, there’s not much to be learned here related to rookie play as a whole. If we compare all rookie season data to post-rookie season data, we get the same splits for both: 19 percent to backs, 42 percent to targets out wide, 26 percent to slot receivers, and 13 percent to in-line tight ends. Rookie-to-sophomore data shows a slight year-two boost for players lined up out wide, with slot receivers losing slightly. It’s not statistically relevant.
Of all 11 quarterbacks, six (or 55 percent) threw to a back more often in their second season. Five quarterbacks (or 45 percent) saw a higher mark in each of the other three categories. Had we been analyzing an even number of quarterbacks, odds are good that we’d be looking at, at least, a handful of 50:50 splits. Again, there’s not much here we can use to project rookie-to-sophomore progression.
Finally, we can compare the rookie data to each quarterback’s future splits. Of our seven experienced quarterbacks, four (or 57 percent) targeted backs more often in year two. Three (or 43 percent) went “wide” or to an in-line tight end more often. Only two (or 29 percent) relied on slot receivers more often. Considering how close most everything we looked at in this section is to 50 percent, not much stock should be put in the slight drops to slot receivers. It’s worth keeping in the back of your mind, though, as we can re-examine this topic again down the road.
Follow Mike Clay on Twitter at @MikeClayNFL