Why Nick Foles Isn't a Sure Thing for the Philadelphia Eagles

Nick Foles had a season quite like no other quarterback in NFL history last year, but it hasn't saved him from being caught up in a bit of a controversy over his starting gig in Philadelphia.

Prior to the NFL Draft, star running back LeSean McCoy hinted that he was in favor of the Eagles' drafting Johnny Manziel, whom Philadelphia could have selected at 22nd overall, but traded the pick to the Cleveland Browns.

Even though the Eagles passed on Manziel, they did bring in Mark Sanchez to fill the backup role behind Foles for one year.

None of this will matter if Foles can continue to play like he did last season though. But can he?

Can anyone?

Foles, in case you need a refresher, threw for 2,891 yards and 27 touchdowns to go along with just a pair of interceptions in 13 games (10 starts for Foles). I'm not sure that anybody is expecting 50 touchdowns and 5 interceptions, but expectations are, understandably, high.

Vegas has set the over/under for the Eagles season at nine wins, and currently, Foles is being drafted as a top seven fantasy quarterback.

Let's pump the brakes though and dissect his 2013 season.

Last year, Foles attempted only 317 passes, tying him for 26th in the league with Jason Campbell. The Philadelphia quarterback ranked 22nd in passing yards, 1st in yards per attempt (9.12), 8th in touchdowns, 1st in quarterback rating (119.2), and 8th in completion percentage (64.0%). These are outstanding marks for such a modest amount of volume, but the efficiency numbers are great benefactors of the low attempt number.

In terms of Net Expected Points (NEP), which is a great metric we use at numberFire that contextualizes a player's impact on his team's scoring based on the player's productivity and factoring in important variables like down-and-distance and field position, Foles's 2013 season is pretty much unrivaled.

He posted a Passing NEP of 108.68 last season, meaning his passes helped earn the Eagles nearly 110 points on the year. This ranked fourth among all quarterbacks behind Peyton Manning (278.52), Drew Brees (175.57), and Philip Rivers (162.80). That mark also ranks 53rd-best since the year 2000.

What's most astonishing is that he did it on 346 drop back attempts, in just his second season in the league.

This is the highest recorded Passing NEP for any quarterback with 346 or fewer drop backs in a season, but second and third on the list are pretty interesting.

Like I noted previously, Foles's 106.86 Passing NEP is tops among these quarterbacks, but two quarterbacks from this season, Aaron Rodgers and Josh McCown, aren't far off. In fact, when using the Passing NEP per pass to project the Passing NEP of Rodgers and McCown, each player would have outproduced Foles.

However, that's not how efficiency tends to work. Plus, Rodgers is a 550 drop back quarterback who happened to be stopped short last season from injury, and McCown is a veteran quarterback with a pretty bad track record who got placed in the perfect system with the Chicago Bears in 2013.

A higher volume, which is something Foles will be facing this season, should provide a lower per-attempt quotient.

Of this year's 10 most voluminous quarterbacks in terms of drop backs, only one of them, Manning (it's always Manning), had a higher Passing NEP per drop back (0.41) than did Foles (0.31). That's to be expected, of course, but what's problematic with Foles' 2013 season is his Success Rate, or the percentage of passes that contribute positively towards a player's NEP.

Now, you can look at the fact that Foles threw a touchdown pass on 8.5% of his pass attempts or that he threw an interception on just 0.6% of his attempts and assume that he's very efficient. You can point to his top eight completion percentage (64.00%) and claim that he's an accurate passer.

You can do these things, but overlooking his modest amount of attempts when you do it is a big problem.

If you recall from the first table, Foles had a pretty low Success Rate (48.55%) on his 346 drop backs, which can't be mitigated. Foles wasn't a high-volume thrower who took a typical hit on success percentages. Instead, he was unsuccessful in adding points to the Eagles more often than he was successful, even with the luxury of the best running back in the league last season, LeSean McCoy. Unlike some of his top 10 stats and fourth-best NEP, this low Success Rate places him in some pretty mediocre company.

Here's a list of the players with the best Passing NEP who attempted between 300 and 400 drop backs while yielding a Success Rate under 50.00% since the year 2000.

Foles' drop backs and Success Rate would have qualified him for this list, and he would have doubled-up the second-best Passing NEP mark from Garrard. His Passing NEP (108.68) also remains greater than the entire tally from the second, third and fourth place quarterbacks from the list (107.90).

How did Foles manage to perform so well while performing so, well, average?

Firstly, having DeSean Jackson helped. Of the 78 wide receivers who were targeted at least 60 times last season, Jackson ranked 12th in Reception NEP (the number of points added on catches only) and 3rd in Target NEP (the number of points added on all targets). And for as much of a big-play perception of Jackson there is, he ranked 12th in catch rate (65.08%), proving he was a solid pass catcher.

Secondly, Foles had the luxury of throwing to Riley Cooper, who wasn't nearly as prolific as Jackson, but someone who did make the most of his catches. Cooper ranked 14th out of the 78 receiver subset in Success Rate (91.49%), meaning that, when he did catch the ball (which he did just 56.63% of his targets), positive things happened for the Eagles. These were mainly touchdowns: Cooper caught 8 touchdowns on 47 receptions - 17% of his receptions were touchdowns.

Unsurprisingly, then, both Cooper and Jackson finished in the top 11 in terms of Reception NEP per target. Cooper (0.90) ranked 10th, and Jackson (0.87) tied for 11th. Their big-play ability was key to Foles' success, and clearly making big plays is a tough thing to repeat year to year.

Foles also had a top 12 pass-catching back. McCoy's Reception NEP of 31.11 was 12th-best among running backs. Shady also finished tied for seventh in terms of Reception NEP per target (0.49). Three of Foles' most-targeted receivers (Jason Avant was targeted 76 times) were elite in terms of making the most of their opportunities, ranking inside the top 11 at their position in Reception NEP per target.

Jackson is now with the Washington Redskins, and Avant is gone, for what that's worth. Rookie Jordan Matthews was drafted to shore up the receiving corps and could be a big hit with the Eagles offense. This leaves Foles with some combination of Jeremy Maclin, McCoy, Matthews, Cooper, Zach Ertz, Brent Celek, and newcomer Darren Sproles.

It's more than a capable bunch of pass catchers, but it's unlikely they'll produce two wide receivers with top 12 type efficiency like Foles had this season. If he somehow manages to overcome his troublesome Success Rate, which is a tall order given the higher volume he'll have this season, then Foles will be the hero in Philly yet again.

If he can't and he ends up producing more like Shaun Hill than Kurt Warner, then he'll need some earplugs to fade out the Sanchez and Johnny Football cheers in the Linc this year.