Two of the best Eagles writers are hashing out the prospects of next year's Eagles on their blogs. Tommy Lawlor is wielding all his Funyuns to support an optimistic view of Eagles advancing, while Brent Cohen is arguing hard that next year anyway, the team is likely to regress. Tommy had a reply, and Brent had a reply to that.

FIGHT! FIGHT! JK, it's an interesting and detailed discussion, well worth reading. I want to look at one specific aspect of this battle, the impact of losing DeSean Jackson, and make a simple point.

The primary difference between the two writers is that Tommy is confident the new receiving corps, with Maclin back and Sproles, Matthews and Huff added, will do better than last year's group, even without DeSean. Brent replies that

Combined, Maclin and Sproles and the Rookies certainly COULD fully compensate for losing Jackson. I just don’t think it’s likely...

There are other disagreements but this is the nub. I'm taking Tommy's side here, for one main reason. DeSean had a great year, but the first few games with Michael Vick at quarterback -- and the ugly period of injuries and Matt Barkley -- were very different than the Nick Foles-based team that came on strong at the end of the year.

That Foles-led team -- starting with the Oakland game -- went 8-1 before losing narrowly to New Orleans in the playoffs. Before that, the Eagles were 3-5. Obviously, the winning unit represents the Eagles going forward. Not just with Foles under shotgun, but with Bennie Logan at nose tackle instead of Isaac Sopoaga, Brad Smith on the team, etc.

On the Foles-led Eagles, though, DeSean Jackson was not as good, and Riley Cooper was much better than he was with Vick. This is obscured by their full year statistics, so I did a detailed breakdown. In earlier discussions, readers noted that you can't simply go game by game, because multiple quarterbacks played in the first Dallas game and both Giants games. Nick Foles also played a bit against Denver, and one snap against San Diego when Vick got hit hard.

So I did a play by play breakdown, separated throws for each of the three quarterbacks, and calculated games by fractions of passes attempted. In the Dallas game, for example, Nick Foles threw 29/49 passes, so he played 0.59 games and Matt Barkley played 0.41. Overall, Mike Vick played 4.62 games, Foles 11.23 games, and Barkley 1.15.

With that statistical precision, the difference is clear. Once Foles took over as QB, DeSean's results dropped from 86.9 yards per game to 76.7, and that number was inflated by two big games against bad defenses, Minnesota (195) and Oakland (150). Pull those out, and during the second half of the year DeSean averaged just 52.4 yards per game -- exactly matching what he pulled in against New Orleans in the playoffs (53).

In contrast, Riley Cooper was much better with Foles running the team. His yardage more than doubled, from 28.2 yds/game from Vick to 56.6 with Foles at the helm (and even more - 60 - with Barkley in). Cooper is obviously no DeSean, but he was actually more of a deep threat than DJax when Foles was throwing (19.3 yards per catch vs. 17.43, even counting the Minnesota and Oakland games)

So if we want to predict how the Eagles will do without DeSean next year, it's important to note that his production was declining with the new starting quarterback, and Cooper's was growing -- even before adding Maclin, Matthews, Huff and Sproles. Instead of asking "can the new guys replace 1.332 yards next year," ask "can those four combine for 53 yards per game." And it's hard not to be optimistic that the answer is "yes."