There are lots of stats you can trot out to make an argument of one versus the other, or that this obviously shows AV is playing favourites versus this stat shows he's playing the guys who provide the best chance to win. Many have tried to use subjective statements to show how obvious it must be, or even the basic stats used by the NHL every day.
Well, I wanted to try and show the reality of how our defencemen our performing beyond our top 4. Settle in for a (hopefully) good read if you're willing.
NAME GP TOI/60 Corsi Rel QoC Corsi Rel Corsi On Off Zone St % Off Zone Fin % AARON ROME 17 12.44 -0.142 -13.2 -0.57 42.3 43.3 KEITH BALLARD 40 13.79 -0.452 -15.8 -1.96 46.3 48.9 ALEX SULZER 12 14.91 -0.084 -2.1 -2.35 41.5 51.1 ANDREW ALBERTS 31 13.15 -0.604 -13.4 -4.42 39.3 50Lets start with the easy stuff: Bieksa, Hamhuis, Edler and Salo are our best 4 d-men, so I've dropped them from the comparisons for now. Of the remaining 4, Ballard has the most games followed by Alberts (31) then Rome (17) and Sulzer (12). Rome's been held back by injuries so likely would have played more. For the rest of the stats, they are strictly 5 on 5 (no PK or PP), since that's the best indicator of their overall play versus any specialized minutes. Of the bottom 4, TOI per game is led by Sulzer (14.91), then Ballard, then Alberts, then Rome. Rome has had less time 5 on 5, two and a half less than Sulzer and over a minute less than Ballard, but there is the time for PP and PK that would factor in if you're worried about that alone. The other stats are meant to augment the 5 on 5 play so let's look at them. Ballard and Alberts are given the easiest quality of competition (Corsi Rel* QoC) out of anyone on our team, and Sulzer and Rome are closer to average opponents (with Rome being almost exactly neutral). Rome, and then Sulzer should have a harder time while Ballard and Alberts aren't challenged as much. *The relative Corsi is a better version of +/- to measure shot differential (goals, saves, missed shots and blocks) for the difference between when a player is on the ice or off it and the QoC version in the table measures the opposition players relative Corsi. For example if a player has more chances for in a game than he does against, he'll have a positive Corsi on ice. If the Corsi when that player is off the ice isn't as good, that player's relative Corsi would be higher still, meaning he contributes more to the team's chances to score. Each of the bottom 4 D's relative Corsi is included (as well as just their Corsi on ice) to show how the chances rate. The bottom 4 typically have more goals, saves, missed shots or blocks against them than they do for them (which you might expect given they don't start as much in the offensive zone), and that's amplified in the relative Corsi since most of our chances 5 on 5 occur when the top 4 are on the ice. Ballard gets the most offensive zone starts of the bottom 4 and Alberts gets the least, but it's interesting to note both Alberts and Sulzer have significant increases from their starts to their finish % in the offensive zone. That means they're doing a decent job of getting the puck back from the opposition (in Alberts case, most likely after a chance where Sulzer may be preventing chances generally to gain possession). Rome trends more towards a defensive zone player and Ballard is slightly more balanced. For comparison, here's the same results for the top 4.
NAME GP TOI/60 Corsi Rel QoC Corsi Rel Corsi On Off Zone St % Off Zone Fin % KEVIN BIEKSA 46 17.66 0.791 7 11.3 47.7 50.7 ALEXANDER EDLER 46 16.25 0.588 6.6 11.24 58.4 54.2 DAN HAMHUIS 46 17.05 0.715 6.1 10.78 48.7 49.6 SAMI SALO 38 13.99 0.599 1.2 9.14 55.4 53.3
You can see their games played and TOI per game is much higher (although Salo is being rested more at even strength). The top 4 D are all 0.6-0.8 roughly for Corsi Rel QoC rather than negative like the bottom 4, so they face the toughest players and the third pairing gets sent out when the bottom lines are on the ice. Salo's a little more neutral in his personal relative Corsi 5 on 5, so that's also worth noting.
The top 4 also have higher offensive zone start and finish percentages (where Ballard leads the bottom 4), and you can see Edler and Salo get a lot of shifts in that zone, as they play with the Sedins most often.
The end result for the bottom 4? In my opinion Rome and Sulzer have been the most reasonable depth guys. Alberts contributes more because of his size and physicality than actual ability, and Ballard isn't obscenely bad but still can't contribute more than the others despite lesser opposition and more offensive zone time 5 on 5.
For the obvious Rome vs Ballard comparisons, Rome plays a simpler, physical game and does well enough, while Ballard has done not quite as well. For his price, he should be better even if his style is limited to less of a risk/reward role than he's used to and it hasn't justified a larger role over anyone, much less Rome.
Data source: BehindTheNet.ca, table sorted by Corsi On Ice.