Nobody questions how valuable Rob Gronkowski has been to the Patriots and to Tom Brady. The future Hall of Fame tight end is a dominant force when healthy, and Brady’s numbers with and without Gronk reflect that. With the PFR game play finder, we can easily look at Brady’s career numbers in the regular season on passes to Gronkowski and to everyone else.

[Note: I still am not a fan of using per-target statistics to judge wide receivers, but I find them an interesting — but certainly not definitive — part of the puzzle when looking at quarterback production. Also note: all statistics in this post are from the PFR game play finder, so they may differ slightly from official numbers.]

Here are a few stats to consider:

• Gronk has seen 8.2% of Brady’s career targets, but is responsible for 10.7% of his career passing yards (+2.6%).
• On passes to Gronk, Brady has averaged 9.95 yards per attempt; on passes to all other Patriots, Brady has averaged 7.36 yards per attempt, a whopping 2.59 yards/attempt lower.
• Thought of another way, Gronkowski has elevated Brady’s yards per attempt by 0.21, as Brady has a career yards / attempt average of 7.57.

So yes, Gronk has been great.  ^[1]And note that using yards is not even the best way to show how valuable Gronk has been.  He’s responsible for 15.3% (!) of Brady’s career touchdowns.; But so has Jordy Nelson, who has been a critical part of the success that Aaron Rodgers has had in Green Bay.  Let’s look at those same numbers:

• Nelson has seen 14.6% of Rodgers’ career passes, but he is responsible for 18.0% (+3.3%) of his career passing yards.
• On passes to Nelson, Rodgers has averaged 9.81 yards per attempt; on passes to all other Packers, Rodgers has averaged 7.67 yards per attempt, 2.14 yards/attempt lower.
• Nelson has elevated Rodgers’ career yards per attempt average by 0.31, as Rodgers has a career Y/A average of 7.98.

Gronkowski being +2.59 Y/A better than all other Patriots is a remarkable figure, and Nelson being at “just” +2.14 doesn’t quite compare.  But due to volume, Nelson has actually raised his quarterback’s career average by a much larger degree.

I used the PFR game play finder to look at the passing breakdown of Brady, Rodgers, and also Drew Brees and Peyton Manning. Some nuggets:

• Marvin Harrison was responsible for 16.6% of Manning’s targets, the highest in the bunch. Brady is the only quarterback of the bunch who didn’t throw even 9% of his targets to one player; Rodgers, meanwhile, has seen four different receivers (Nelson, Randall Cobb, Greg Jennings, and James Jones) on the receiving end of at least 9% of his passes. This is in part because Rodgers has had a shorter career, and also the general lack of roster turnover in Green Bay.
• More than any other quarterback, Brees has made a living off of secondary weapons. Kenny Stills (11.82 yards/target, 133 targets), Robert Meachem (10.74, 251), and Devery Henderson (10.27, 384) were the only three players to average over 10 yards per target on at least 100 targets.
• Brees throws a ton to running backs, and they also kill his average. Among players for these four quarterbacks who were responsible for at least 2.5% of their quarterback’s targets, Brees has the three players with the lowest average gains: LaDainian Tomlinson, Reggie Bush, and Mark Ingram.
• Nothing stands out immediately to me about Manning: as you would suspect, Reggie Wayne, Harrison, and Demaryius Thomas are the three who have helped him the most, but not to a particularly noteworthy degree. Harrison had the most targets, Wayne bumped his average up the most (+0.16), and Thomas had the best average gain (9.32).

I’ve reprinted the raw data below for all players who were responsible for at least 1% of the career targets for each quarterback. Here is how to read the table below, which is sorted by career targets, using the top row as an example.

Harrison saw 1,544 targets from Manning and gained 12,732 yards on those targets, an average of 8.25 yards per target. That’s +0.54 relative to Manning’s overall average (which includes Harrison’s numbers), and the “value” Harrison added is 835 yards (0.54 * his number of targets). Harirson saw 16.6% of Manning’s targets but 17.7% of his yards, a difference of +1.2%. Finally, he increased Manning’s overall Y/A by +0.11.

Finally, the raw numbers for each quarterback:

Rodgers: 38,542 yards, 4828 targets, 7.98 Y/A
Manning: 71,859 yards, 9326 targets, 7.71 Y/A
Brees: 70,429 yards, 9151 targets, 7.70 Y/A
Brady: 66,114, 8731 targets, 7.57 Y/A