-4.6%
Drafting a quarterback is scary. The chance for bust; the chance of being burdened with a must-start failure; the chance of crippling Seattle with a huge contract and no chance of contention for seasons to come - It's intimidating. It's downright terrifying. But it must be done. Seven of the top ten quarterbacks in DYAR were drafted in the first round. Fourteen of the thirty two starting quarterbacks, from phenoms like Matt Ryan and Joe Flacco to competent retreads like Kerry Collins and Chad Pennington, were selected in the first round.
Still, the temptation to cheat, to find a lower risk talent through free agency ,or stashed on some stacked team's roster, remains strong. Thus, Matt Cassel.
In 2007, Tom Brady averaged a 56.9% DVOA. DVOA measures team performance more accurately than individual performance. Better said, the 2007 New England Patriots passing offense averaged 56.9% DVOA with Brady under center. That's system, Randy Moss, Wes Welker, Ben Watson, etc. and Tom Brady.
In 2008, in the same system, with Randy Moss, Wes Welker, Ben Watson, etc. Matt Cassel has averaged a -4.6% DVOA. That's a 60% swing. That's the difference between Matt Ryan and JaMarcus Russell, except cleaner and more damning. Ryan joined an offense loaded with talent awaiting competent coaching and quarterbacking. Russell toils on the most tumultuous and worst run franchise in the NFL.
Brady himself likely wouldn't have continued his torrid run. Peyton Manning posted a 62.8% DVOA in 2004, but a measly 41.7% DVOA in 2005. Quarterback DVOA spikes and sinks - just not like that. That's not natural regression. That's a whole other animal.
Cassel turns 27 May 17. He didn't start at USC buried behind Carson Palmer and Matt Leinart. Cassel was in real danger of being cut before the 2008 season. He inflates sacks. He's shaky in the pocket. His production is hugely dependent on his surrounding talent's yards after catch. Welker's yards after catch is up over a yard from last season. Moss's yards after catch is up nearly two.
We've been here before. Derek Anderson was the vogue free agent to be after a remarkable spike in play. A season later he was benched. Cassel joined an offense that humbles him with its talent. That he's its face does not mean he's its cause or even instrumental to its success. Cassel might be a serviceable quarterback. He might be a total bust. He has almost no chance of being a great quarterback. And no team should build its future around him.
Seattle needs a quarterback of the future. And that quarterback should be, better be, a riveting, terrifying, make or break first round pick*.
* Or Brian Brohm.