On draft day, when the Canucks made the call to trade future NHLer Michael Grabner and a first round pick for Keith Ballard and Victor Oreskovich, they were taking a big gamble. What's interesting is, while Oreskovich has played the majority of the playoffs on the fourth line, (and well) Alain Vigneault seems unwilling to give Keith Ballard a chance, with Ballard having been a healthy scratch twice, playing under 14 minutes a game and sitting out of Game 3 against Nashville.
Ballard seems to be going in-and-out on a rotational basis with Aaron Rome and Andrew Alberts, so it might be worth to compare how the three players stack up against each other. Traditionally, Ballard was a plus-10, Rome a plus-1 and Alberts even over the course of the regular season, but we'll dig a little deeper.
Corsi is a number that tracks the number of shot attempts taken at your opponents net subtracted by those against your own net. It works as an expanded plus/minus, but, along with it comes a lot of noise. Players that go up against stronger competition or start more of their shifts in the defensive zone are at a disadvantage when it comes to Corsi. These stats can be found at Behind The Net.
The average relative Corsi rating of Andrew Alberts' opponents this season was -.485, the lowest of the three. Rome's was .053 and Ballard .175. The takeaway from this is Alberts plays against easy competition, the easiest of the Canucks who dressed for more than 20 games this season. Despite this, Alberts put up a relative Corsi rating of -15.2, the lowest among Canucks defensemen.
Secondly, zone starts. A player's Ozone% is determined by the shifts started in the offensive zone divided by all shifts started, minus those in the neutral zone. Rome was at 44.2% and Ballard at 44%, so, there's some similarity between Rome and Ballard.
Where Ballard's plus-10 rating seems to come from is that he benefits from playing in front of the best goaltending, a .948 save percentage at even strength, which is among the highest in the league. This inflates his rating to the point where his mistakes aren't as visible as Rome's.
If Aaron Rome belongs on the ice, as per Vigneault, so does Keith Ballard. Andrew Alberts, however, should be the odd-man out in this regard.