Los Angeles defencemen with at least 100 games played between 2007-08 to present, ranked by plus/minus rating per 82 games played:
1. Sean O'Donnell, +8
2. Rob Scuderi, +6
3. Drew Doughty, +4
4. Willie Mitchell, +4
5. Matt Greene, +2
6. Davis Drewiske, -3
7. Peter Harrold, -5
8. Jack Johnson, -21
Obviously, Jack Johnson is not very good, yet apparently he and a first round pick are worth Jeff Carter, a guy who scored more goals in the three seasons prior to this one than every player in the league save Ovechkin, Crosby, Stamkos and Marleau.
Just as I prefer to look at multiple seasons' worth of data for goalies, I think there is at least some value in multiple years' worth of plus/minus given how the percentages tend to work themselves out over the larger sample, although obviously matchups and usage context are still important, especially for players utilized in a specific role.
However, when you're supposed to be one of the best defencemen on your team and you're that much of an outlier in terms of getting outscored over a 338 game sample despite not playing tough minutes, it's pretty glaring. It's also very tough to make a linemates excuse given that Johnson had four different defencemen rank as his highest defensive teammate TOI over that span, not to mention also having the benefit of playing more minutes with Anze Kopitar than any other Kings forward in four of the five seasons (it probably would have been all five if Kopitar played 82 games in 2010-11). At some point there's really nobody else left to blame. And the bad news for Blue Jackets fans is that their team is on the hook for paying Johnson $4.357 million per year through 2017-18.