Aaron Schatz of Football Outsiders wrote an interesting article for ESPN.com about the retirement of Jonathan Ogden that might provide some comfort for Vikings' fans worried about the almost inevitable suspension of Bryant McKinnie. In the article, he argues that the loss of a Hall of Fame caliber lineman doesn't hurt a team as much as would be expected by comparing the statistics from 45 teams from before and after losing a top linemen.
Those 45 teams barely experienced a drop in their adjusted line yards and their adjusted sack rate, the stats that should be most effected by the loss of a top lineman. Now, the Vikings won't be losing a Hall of Fame lineman, but they will be losing a good one, though it won't be permanent, like the lineman lost by the teams looked at in the article.
One of the reasons for teams ability to weather losses that was advanced in the comment section is that teams were able to plan to replace lineman lost to free agency or retirement (like what the Vikings are doing this year at the center position). While that idea has some validity (which doesn't bode well for the Purple, as they haven't really done anything extra to prepare for McKinnie sitting out), those numbers include unexpected losses, such as Seahawks losing Steve Hutchinson to free agency, or the Vikings' losing Korey Stringer after he passed away in training camp, which would seem to dispel that theory (and bodes well for the Vikings).
The article itself does not advance a theory as to why teams are able to weather the loss of an elite lineman, expert for some vague mention of continuity being important. If that's true, that's probably good, since Artis Hicks, his presumed replacement, has been on the team for two years, and should have a decent comfort level with Steve Hutchinson and the rest of the linemen. Will he be as good as McKinnie? Probably not. Will he be able to step in and provide a decent replacement for the 2/4/8 games that McKinnie has to set out? I really hope so.