Prior to the season, I examined how the Eagles have historically used a variety of different offensive and defensive personnel packages. Now, I'm going to take a look at the packages used in 2012 and check on how successful each of them has been.

Offense – Passing

The Eagles' base offense is, of course, the 3-1-0-1. Assuming full health, the package will generally feature Jeremy Maclin and DeSean Jackson on the outside, Jason Avant in the slot, Brent Celek at tight end and LeSean McCoy in the backfield. This package has been in place on 83 of the team's 181 offensive plays (46 percent) this season.

The results, as you can see from the chart above, have been excellent. Michael Vick is averaging 9.8 yards-per-aimed-throw* and has completed 70 percent of his aimed passes. Both are significantly higher than his marks on throws not made with the 3-1-0-1 package on the field.

*Aimed Throws = Pass Attempts minus batted balls, balls disrupted by a hit, spikes and throwaways.

Interestingly, the offense has been considerably less productive when a wide receiver is removed in favor of a second tight end (Clay Harbor). Vick's completion percentage is 15 points lower and his YPA drops by 2.3 yards. He's actually been more successful when fullback Stanley Havili is on the field. Considering that Harbor has been asked to block 36 percent of the time when he's on the field for a pass play (compared to 29 percent for Havili), however, I don't have a perfect explanation for this. Of course, we're only talking about 67 total snaps here, so it could simply be a sample size issue. We'll monitor this as the season progresses.

Finally, I wanted to touch on the 12 plays where Vick has had the most targets, but the fewest pass blockers. In the two four-wide receiver sets shown, Vick has completed just 4-of-9 aimed throws for 26 yards. He felt pressure on six of those snaps, threw the ball away twice, had one pass batted down and was sacked once. Vick simply isn't getting enough time to throw without additional protection.

Offense – Rushing

Our next chart focuses on the personnel packages utilized when the Eagles run the ball.

(one extra offensive lineman on the field)*

Earlier, we learned that the Eagles' preferred and most successful offensive package on a pass play is the 3-1-0-1. We see similar results here. The Eagles have called on the 3-1-0-1 on 41 percent of their run plays this season and had plenty of success. Led by McCoy, the unit has averaged 5.8 yards-per-carry, which is well above the offense's 3.7 mark in other packages.

Although the three-wide package has been successful, adding a fullback and removing one of the wide receivers has been the best case scenario for the offense. The 2-1-1-1 package has put up 6.7 YPC. Again, we see that this package is significantly more productive than the two-tight end set, which is putting up only 3.6 YPC.

Notice the team's production in what are generally short-yardage and/or goalline sets. In situations where one fullback and a pair of tight ends are on the field (fewer than two wide receivers), the Eagles have lost 12 yards on 13 carries.

Defense – Passing

Next up, we'll take a look at the packages in place when the opponent calls a pass. Obviously, defensive coordinator Juan Castillo doesn't know what play the offense will call, but he, of course, is making an educated guess based on game situation, down, distance and offensive personnel.

The Eagles' "base" defensive formation is technically the 4-3, but, as was the case in 2011, the nickel is usually on the field more often. This, of course, is a product of the league leaning more and more towards the pass.

As you can see from our first chart, the nickel (4-2-5) has been on the field for 87 opposing quarterback drop backs. This will generally involve nickel corner Brandon Boykin replacing linebacker Akeem Jordan. The results have been strong, with quarterbacks averaging just 5.8 yards-per-aimed-throw and completing only 54 percent of aimed passes. It does not look like Boykin is much of a "candy bar" after all!

On the other hand, when in the 4-3, the Eagles are giving up an 8.3 YPA and 60 percent completion rate.

While it is a very small sample size, opposing quarterbacks have completed only 40 percent of their throws with a 3.4 YPA on 14 drop backs against the Eagles' dime (4-1-6) package.

Defense – Rushing

Finally, we have the breakdown of Eagles' defensive packages when the opponent runs the ball.

Here we see that the 4-3 is on the field nearly twice as often as the nickel when a run is called. Opposing backs are averaging 3.4 yards per carry against the Eagles' 4-3. That compares to a league-average 3.7 YPC mark against the 4-3.

When the Eagles get caught in the nickel against a run, they surrender 4.5 YPC. That compares to a league-average of 4.9 vs. the same package. Another positive.

Considering that the 4-3 or nickel has accounted for 92 of the team's 95 defensive plays against the run, that's really all we need to investigate here. The 7.5 YPC on a pair of carries against the Dime is about what you'd normally expect in that situation.

That's a wrap for this week. Keep an eye on the personnel packages this week against Pittsburgh to see which are the most successful. Check out InFocus throughout the season for the most comprehensive Eagles analysis on the web.

Mike Clay, @MikeClayNFL on Twitter, is the Director and Managing Editor at Pro Football Focus Fantasy. He also works as an NFL Writer for NBC's Rotoworld.com.