Kaberle was signed as a free agent this summer to a three-year contract worth $12.75 million (cap hit: $4.25 million per year). Carolina GM Jim Rutherford regretted that move, especially as the Canes are a budget team. Spacek's salary is not a whole lot less ($3,833,333), but at least he's a free agent at the end of this season.
The Hurricanes get: 1) Cap relief plus the ability to undo what they believe was a mistake in giving Kaberle such a lucrative contract, and 2) a physical, two-way defenceman who provides cap/contract flexibility this summer.
The Canadiens get: 1) A proven PP QB, albeit one who has struggled since leaving Toronto, and 2) a somewhat expensive contract.
My take on how this will impact specific players below...Impact on the Canadiens:
All forwards on the Habs PP: +
The change of scenery should do Kaberle some good. Could he really be worse than he's been for Carolina? (and prior to that, for Boston) Kabs will be given ample opportunities to jumpstart the struggling Montreal power play. To the extent he is successful, that rising tide should lift all boats--i.e., the forwards who see regular time on the PP. This will mean a reduction in PP time, however, for Montreal's other blueliners: Campoli, Diaz, and Weber. Hopefully, you weren't counting on those guys anyhow, as it will be the Kaberle and Subban now.
Impact on the Hurricanes:
Kaberle was receiving 3:58 ATOI on the PP in Carolina--second on the team to Pitkanen. Spacek won't play on the PP, so no change in value to Pitkanen or Spacek, but with Kaberle out of the picture, the D next in line (McBain, Faulk) will see an increase in their PP time and a boost in their value.