Thursday, August 22, 2013
Do numbers really support Jags, Gabbert?
By John Parolin & Jason Vida
Jeff Zelevansky/Getty ImagesThe Jacksonville Jaguars have been one of the most aggressive NFL teams in the use of advanced metrics to quantify performance. Writer David Fleming profiles the Jaguars’ analytics department in an article in the new issue of ESPN The Magazine.
Despite his past struggles, the Jaguars have put their trust in Blaine Gabbert heading into 2013.
Tony Khan, the son of the team owner and the person who oversees analytics for the franchise, explained in the article how data analysis helped convince new coach Gus Bradley to give Blaine Gabbert another shot in 2013.
Khan said the case for Gabbert was based on three statistical points:
1. Though Gabbert’s NFL passer rating was 70.2 since being drafted (second lowest in the league), it was a “respectable” 82.2 in 2012 when adjusted for drops, throwaways and spikes.
2. When facing a six-man rush, Gabbert ranked first among quarterbacks in completion percentage.
3. The Jaguars’ offensive line gave Gabbert an average of 2.56 seconds to throw the ball. When given more than 2.6 seconds, his NFL passer rating jumped to 84.5.
Another view of the data tells a different story.
Adjusting for drops/throwaways
According to ESPN’s internal video tracking (which may define drops and throwaways slightly differently), Gabbert actually had an 85.1 NFL passer rating without drops, spikes and throwaways last season.
However, when those plays are ignored for all quarterbacks, the league-average passer rating jumps to 93.4, more than eight points above Gabbert.
The six-man rush
Gabbert did complete a higher-than-average percent of his throws against six-man rushes, but defenses rushed six or more players on fewer than 8 percent of all dropbacks last season.
On the overwhelming majority of passing plays with defenses rushing five or fewer defenders, Gabbert completed 58 percent of his passes, 27th best in the NFL.
Time in the pocket
The article cites a passer rating jump to 13th from 25th on plays with 2.6+ seconds in the pocket. However, his Total QBR shows only slight improvement, from 40.6 to 43.9 (a seven-spot jump in the ranking). Two factors cause this:
Gabbert’s completion percentage is high (seventh in NFL) with 2.6+ seconds in pocket because his average throw distance ranks 31st in the league. That will help his passer rating, but not necessarily his overall performance or Total QBR, which factors in the distance the ball travels from the line of scrimmage.
Also, Gabbert’s sack rate at 2.6 seconds in the pocket was 31st in the league last year, something NFL passer rating doesn’t consider at all.
Gabbert’s career sack rate after 2.6 seconds in pocket is the worst among 33 qualified quarterbacks in the last two seasons.
A fundamental assumption of the Jaguars’ case for Gabbert was his improved performance if the line gave him time to throw. There already is data to examine Gabbert’s performance without pressure from pass rushers.
Gabbert's Total QBR when not under pressure (under duress, hit while throwing or sacked) ranked 31st of 36 qualified quarterbacks. The only quarterbacks with a worse QBR “not under pressure” were Chad Henne, Mark Sanchez, Brady Quinn, Matt Cassel and Brandon Weeden.
There were 39 quarterbacks with 150 pass attempts last season when not under pressure. Gabbert is one of four quarterbacks who have an off-target percentage above 20.0 (Kevin Kolb, Josh Freeman and Ryan Lindley). Freeman's average pass when not under pressure also traveled 10.2 yards downfield, the highest in the league, and Gabbert’s 7.9 ranked 24th.
His low “throw distance” under pressure didn’t equal success. Gabbert completed 64.7 percent of passes thrown 10 yards or fewer downfield when under no pressure. The only other quarterback who completed below 65 percent was Mark Sanchez (64.6).
The inefficiencies in Gabbert’s passing showed up in his 6.2 yards per attempt when not under pressure, worst in the league among qualified quarterbacks.
Evaluating whether a young quarterback is the right fit for a team is a critical decision. Total QBR accounts for most of what the Jaguars were trying to evaluate using a series of statistical splits. QBR uses all of a quarterback's plays (including sacks and fumbles) along with additional information like distance passes are thrown, the number of rushers, drops, throwaways and spikes to divide credit between the quarterback and his teammates.
Entering his third season, our measures indicate that Gabbert hasn’t earned the Jaguars’ trust.