Philip Rivers Stat Tracker: Week 3

Thanks to the nflFastR project and NFL NextGen Stats for the timely sources of data. Commentary will be brief but feel free to let me know in the comments that stats aren’t everything. (click charts for larger view)

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HOW WELL?

Being pulled in the 4th quarter tends to reduce one’s overall volume, but on a per dropback basis, Philip Rivers looked great. Two-thirds of his passes added positive value and his EPA efficiency was up with the big boys.

All 4 of the key stats were fantastic. First downs per dropback was literally off the chart and had to be re-scaled. That is good to see as, other than the week 1 picks, that was my biggest concern. If you are moving the chains with your arm, then everything else likely takes care of itself.

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HOW FAR?

The game started with some longer passes, but in the 2nd half, the passing game got conservative with Rivers attempting only 1 pass longer than 10 yards. That’s to be expected with a 2-3 score lead . . . not sure what week 1’s excuse was.

In the next graph, you can see the average depth of target dropped back to about week 1 distance (left chart gold line), primarily driven by a conservative 2nd half. However, the completed passing length was the best so far this year (blue line).

Since passing length and YAC have seemed to be a topic of conversation lately, I thought I would add a chart comparing that for all QBs. In the following graph, the height of the bar is yards per attempt (which is the more critical measure), but the graph is sorted by completed air yards per attempt (cay/att).

Rivers ranks 6th in YPA but 20th in terms of cay/att (right above of Gardner Minshew) and 4th in average YAC.

That could be an issue if YAC is not sustainable, but it depends on many variables. Simply saying high YAC + low cay/att = bad QB is no analysis at all. Both Drew Brees and Patrick Mahomes have far lower cay/att and similar avg YAC.

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Rivers continues to NOT throw TD passes from far away. If our red zone woes are to go away, he’s going to have to do better.

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TO WHO?

Call me old-school, but I don’t think your 2nd string tight end should be leading the team in season long receiving.

Notice on the year (right chart), that the wide receivers are below the NFL average line in EPA value. That is a problem.

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HOW ACCURATE?

Rivers continues to be one of the most accurate QBs in the league and that is after adjusting for his shorter depth of targets (5th cpoe).

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HOW FAST?

He hasn’t taken sacks and gets rid of the ball quickly. That works for me.

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TO WHERE?

Of 36 QBs who have at least 10 passes > 10 yards, Rivers has the 9th best EPA efficiency on the 13th most attempts. Yes, you read that right.

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GLOSSARY

Dropbacks (db): Attempted passes, Sacks or QB scrambles with QB spikes removed.

EPA per Dropback (EPA/db): For any given down, distance and field position, there is an average amount of points the team is expected to generate from that spot (EP). After the play the added EP (EPA) is calculated. EPA/db is the average of EPA for all QB dropbacks.

Passing Success Rate (PSR): This is the % of passes that were successful. Success is determined by dropbacks that have an EPA > 0. This is useful, as it evenly weights all dropbacks, so that extreme EPA events can’t bias the measure.

First Downs per Dropack (1st %): The percent of dropbacks that result in a first down.

Net Yards per Attempt (NY/A): Passing yards plus scramble yards minus sack yards divided by dropbacks.

Air Yards (ayd): The distance a pass travels through the air past the line of scrimmage. Passes behind the line of scrimmage have negative air yards. Batted down passes have 0 air yards.

Average Depth of Target (aDOT): Total air yards divided by attempts. It is a measure of how far, on average, a QB throws. Longer isn’t necessarily better but below a certain threshold and moving the ball is difficult.

Yards Before the Catch (YBC): The air yards on a completed pass.

Completed Air Yards per Attempt: This is average YBC. It’s like aDOT but excludes incompletions.

Yards After the Catch (YAC): The distance gained by a receiver after catching a pass.

Completion Percent Over Expected (cpoe): The percent of passes completed above expectation based on air yards, field placement and other variables. This is a proprietary stat provided by nflFastR.

Time to Throw (TtT): The number of seconds from snap to release on passing attempts.