Seattle probably didn't need to sign Julian Peterson. His primary strength, rushing the passer from the linebacker spot was already adequately filled by Leroy Hill. The downside of signing Julian Peterson last year was that it forced Leroy Hill into the strong side linebacker position. For Seattle, the SLB is used frequently in coverage, a move against Hill's two primary strengths: run stopping and pass rushing. In light of this season's free agent frenzy, it's hard to argue Peterson's value--he was guaranteed roughly the same amount of money ($18 million) as the older Adalius Thomas--but one can argue his fit. His value to the Seahawks is slightly offset by Hill's decline.
Reading Hill's scouting profile you can understand why Seattle thought he would be able to succeed in coverage, but what can't be timed or weighed is a player's ability to read an offense and anticipate a receivers rout. Hill wasn't too slow or too small or too weak to cover his man, he was just clueless as to where they were going. This forced Hill to play exceedingly soft, and, thus, ineffectively. Recording tackles but allowing catches. In Kansas City, Hill recorded six tackles, but Tony Gonzalez caught six passes for 116 yards.
Coverage is one of slowest skills for a young defender to learn. As a linebacker Hill plays in short hook zones, usually five to ten yards from the line of scrimmage. His two major responsibilities from this position are tight ends and running backs. Seattle, like over half the teams in the NFL, performed well covering running backs. That's the result of a lot of dump-offs in pressure situations. Despite dropping from 10th to 16th place, Seattle's defense showed improvement from 2005 at defending against receiving backs, -10.2 DVOA in 2006 vs. -8.5 DVOA in 2005. In this regard Hill played well. Seattle was spared the Brian Westbrook's of the league, instead facing the ordinary class of back that almost exclusively runs hook and screen patterns. Hill's job here is pretty simple, keep his man in front of him and limit yards after the catch. The one team and running back capable and willing to run a more advanced rout, Kevin Jones in the Mike Martz offense, recorded 45 yards on five catches. That's not a hollow 45, either (i.e. one 41 yard reception and four one yard dump-offs), Jones recorded 4 receptions of 9 or more yards. Against tight ends, Hill was exposed. Besides strong performances from Gonzalez and Antonio Gates, everyone from Eric Johnson to Jermaine Wiggins recorded quietly productive games.
Hill is not hopeless in coverage and the ideal solution for Seattle would be to give him time to grow into his new role. That doesn't mean the Hawks shouldn't have a backup plan. By early next year Hill may have played himself into being a two down linebacker, if that happens, a viable third-down linebacker, especially one who excels in coverage should have been acquired through the draft. A player like Quincy Black offers a tantalizing combination of size and athleticism, but perhaps not the needed coverage awareness. KaMichael Hall has a good reputation in coverage, but his 7.5 performance in the cone drill hardly sparks excitement about his agility. Nate Harris sort of splits the difference between the two, with a better closing burst than Hall and a better coverage reputation than Black.