There's a pretty simple explanation for Nick Foles' erratic start to this season.

The Eagles quarterback is throwing far more deep passes than he did last year - and far more than any other NFL quarterback this season - and he's having less success completing those attempts than he did last season.

"I've definitely just tried to take some shots, try stretching them out a little bit," Foles said Tuesday. "I need to be a little bit more accurate. That's what I'm working on this week. . . . Delivering the ball to the guys to where they can go make a play, not where the ball lands in front of them."

Foles already has thrown 39 deep passes (more than 20 yards) in four games, according to numbers from Pro Football Focus. That's 17 more than the two closest quarterbacks, Matt Ryan of the Falcons and Philip Rivers of the Chargers.

Yes, he's passing more because of the ineffectiveness of the running game, and his percentage of deep throws per attempt (23.5 to 17.4) this season compared with last isn't as drastic, but the number projects to 156 over an entire season.

The Ravens' Joe Flacco tossed a league-high 88 deep passes last season. Foles' 39 deep balls represent an abnormal number, and perhaps it will balance out over the course of 16 games, but the greater concern is his inability to connect.

Foles has completed 10 of 39 deep passes (25.6 percent) for 272 yards and four touchdowns and has tossed three interceptions. The top deep passers this season are slightly above or under 50 percent.

It's not as if Foles didn't chuck the ball downfield last season. Projected over an entire year, only three quarterbacks would have had more deep pass attempts. But no one was as efficient. Of Foles' 55 deep throws, 25 were caught (45.5 percent) for 14 touchdowns. He threw only one interception.

His production was astounding, and given the small sample, it's fair to suggest that it was an anomaly. Foles' numbers this season are more in line with the league average in terms of accuracy. There's a reason quarterbacks don't heave bombs all game - they're harder to complete.

But Foles has been errant on some deep passes he probably should have hit. Wide receiver Jeremy Maclin has been getting open often, which may justify the disproportionate number of attempts. Foles has started to find him after overlooking him several times in the opener, but the throws have mostly been off.

Coach Chip Kelly said there were four passes against the 49ers on Sunday that Foles overthrew. In the second quarter, he had Maclin running a post against one-on-one coverage and getting inside separation. When Foles cocked his arm, he had a clean pocket, but he threw slightly off his back foot. He had enough arm strength, but the ball was behind Maclin and he had to adjust his route.

"It's just simple things," Foles said. "It's footwork. Just keep my feet solid underneath me. Get more push in the pocket. Being able to transfer my weight. It's things I can correct."

Foles clutched his left shoulder in each of the last two games after hits. He said that "it's just a couple of bruises" and that it wasn't affecting his throws. He also shot down the idea that he has had to adjust the projection of his long passes without the departed DeSean Jackson.

Seven of Foles' 25 deep-ball completions were to Jackson last season, but Riley Cooper also had seven. Cooper has only one catch beyond 20 yards this season and has the lowest yards-per-route-run average among NFL receivers who have been targeted at least 25 times.

Foles hardly deserves all the blame for the loss to the 49ers or whenever the big-play offense has faltered. Injuries on the offensive line and the errors of others have factored into his below-average completion percentage (57.8, which is 29th in the league) and his passer rating (81.7, which is 25th).

"I think obviously we set a very high standard here in terms of the success we had last year," Kelly said Monday when asked to assess Foles after four games. "But there's a different group of guys playing right now, and I think that's the reality of it."

It's not as though Foles is playing poorly. He was uneven in the Jaguars, Colts, and 49ers games but was great against the Redskins despite sustaining a number of blows. The 25-year-old quarterback is still only 20 starts into his career.

Just as the disparity in his deep passing this season compared with last has shown, it's still too early to draw any conclusions about Foles. That's what this season is partly about. There are 12 games left before any cogent argument can be made.