Eagles TE Drop Percentages

Posted on August 14, 2013

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Part of training camp in the Twitter era is receiving practice play-by-play. Many reporters have alerted fans to Brent Celek’s frequent drops over the course of this camp, and some (at least Sheil Kapadia [1,2] and Jimmy Kempski [1,2]) have explored, in varying degrees of depth, the historical drop rates of Brent Celek, Zach Ertz, and James Casey. This post is simply an extension of what they’ve already looked at, putting all the data for all three players into one post.

Name

Team

Targets

Rec

Drops

Catchable

D/Catchable

ALL

James Casey HST

96

70

3

73

4.1%

ALL

Brent Celek PHI

420

287

35

322

10.9%

2012

Zach Ertz STAN

103

69

11

80

13.8%

That’s it. (You can skip the rest if you don’t care how I found these numbers.)

Process:

The data for Casey and Celek comes from Pro Football Focus. For Ertz, Jimmy Kempski had referenced an article where Greg Peshek watched Ertz’s tape and published a drop rate of 10.68%. While the article didn’t explicitly say so, Peshek confirmed to me via Twitter that it was for 2012. I pinned Ertz at a 13.8% drop rate because I’m fairly confident Peshek calculated by dividing drops by targets, but I prefer drops/catchable. Peshek did not report the actual number of drops, catchable passes, or targets, but I believe I accurately determined those numbers by knowing he had 69 receptions last year, per CFBStats.

10.68% = 11/103 … Ertz had 69 receptions last year … 11/(69+11) = 13.8%.

11 and 103 are the only reasonable numbers that yield 10.68%. So Drops = 11. And 103 can’t be catchable balls because 69 catches out of 103 catchable balls is not feasible. 103 does make sense as targets.

Additional Context:

Casey (who played in the backfield more than the others) didn’t run as many deep routes as Celek or Ertz. I do not have access to PFF’s average depth of target (ADOT) because that is exclusively accessible via their Fantasy Package, and I do not play fantasy football. But using 2012 data from Football Outsiders, I calculated Celek’s ADOT as 7.4 yards and Casey’s as just 3.4 yards. And while not perfectly comparable, 9.64 of Ertz’s 13.56 YPC were Air Yards, per Peshek.*

Comparing their ADOTs is relevant not only in understanding how they were used, but depth of target also seems to have a small effect on drop rate. That’s a topic for a future post (unless the analysis has already been done elsewhere), but for now I’ll just note that having run shorter routes likely gives Casey a slight boost. Drops took place an average of 8.6 yards downfield, while completions took place an average of 6.7 yards downfield. HBs and FBs in 2012 combined for a drop rate of 9.2%. TEs 9.3%. WRs 9.6%. So you can see the trend. But without doing a full-blown analysis of how much depth of target affects drop rate, it seems weak enough that even if adjusted for this, Casey would still come out ahead.

And for those wondering, recently-converted-to-WR Clay Harbor has a career drop rate of 11.3%

*CFBStats credits Ertz with a significantly lower figure of 13.01 YPC. I played with excluding Stanford’s Bowl Game, but still never got near Peshek’s value, which implies a season yardage total about 30 yards greater than CFBStats reported. Regardless, Ertz clearly was used vertically.

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Posted in: Eagles, Uncategorized