I want to say this before its too obvious. Polak is better for the team than Zaitsev. Both are chippy, but Polak is playing for his life, Zaitsev is richer than anyone on the team save Babcock. Polak is just beasting it.
I'll give you this. If Polak starts playing like he did last year down the stretch and into the playoffs, I'll take him over a completely panicked Zaitsev. Maybe he's the Claude Lemieux of depth defenders?