What Marino, McNabb have in common

And no, I'm not talking about their lack of a Super Bowl ring. Soon after the Eagles sent Donovan McNabb to the Redskins for a second-round draft pick in 2010 and a potential third-rounder in 2011, the folks at Football Outsiders broke out their calculators and went to work.

Aaron Schatz, the patron saint of FO's similarity scores system, compared McNabb's past three seasons to the three-year spans of quarterbacks who put up similar numbers. Dan Marino's 1990-92 seasons quickly caught Schatz's attention. And Archie Manning, Brett Favre, Phil Simms and Jim Kelly were also in the mix. This information is so privileged that we make you pay (a reasonable amount) for it via Insider status. But here's an excerpt from Schatz's fascinating study, which was published April 5:

When you look at their numbers, you wonder whether McNabb will give the Redskins that much more than they got from Jason Campbell, writes Schatz. Let's imagine McNabb's 2010 season will look like the average performance of those 10 similar players in the season following the three-year span listed above. Those players averaged 13 games, primarily because of injuries, but we prorated the average to 16 games. We then compared these expected numbers to Campbell's stats in 2009.

The McNabb comparables ended up with a better touchdown-interception ratio (22-to-14, compared to Campbell's 20-to-15); the yardage (3,411 for the McNabb comparables to 3,618 for Campbell) and completion percentage (60.8 for McNabb comparables, 64.5 for Campbell) don't match what Campbell did this past season. Yes, McNabb averaged more than 8 yards per attempt this past season, but that was a yard more than what he averaged in 2007 or 2008, and he doesn't get to bring DeSean Jackson with him to Washington.

Of course, Campbell had the lowest average per attempt in the league in '09, in part, because he was playing behind an inferior offensive line that forced him to unload the ball early. But FO's research seems to indicate that McNabb's presence alone won't lift the Redskins into the playoff conversation.

In '09, he was surrounded by a talented receiving corps and he played behind a decent offensive line. Perhaps Mike Shanahan's commitment to the running game will take pressure off McNabb, but I'm not sure this will go smoothly. What do you guys think?