I'll give my take again, it's not going to show Pionk in the best of light, but it may show him in a lesser evil light.
This season, Even Strength
Pionk has 138 mins with Staal, 92CF 161CA, a negative 69.
Pionk has 64 mins with Skjei, 66CF 80CA, a negative 14.
There is a pretty big difference between his ratio when he plays with Staal versus when he plays with Skjei. Even if that were extrapolated out to roughly the same minutes, it's basically a negative -28 when with Skjei versus a negative -69 with Staal.
It's still not good but there must be reasons for the difference based on partner.
(I am sure someone will bring up Staal without Pionk doing better in those metrics, and he does but Staal's next most common partners in minutes have been Smith and Shattenkirk, two players that usually put up good shot based metrics and have done so with Staal so far this season. Oddly enough those two, Smith and Shattenkirk as a pair have lesser good metrics together than they do when either is paired with Staal.)