The only thing that changed after Nov was the PP got cold and once that happened his point production literally died.
He was the injury replacement for Bonino, he was the replacement for Richardson. He didn't deliver when he was with Vrbata and Higgins and he didn't deliver when he was with Matthias or whoever.
He just didn't deliver with anyone after the PP cooled down.
Quick tally shows Vey was:
~.42ppg through to the end of 2014 calendar year.
~.395ppg through the month of January.
~0.21ppg from Feb to End of Year (which includes a bit of top PP opportunity before it tailed off sometime in that eastern swing and become completely intermittent, Weber "the guy").
If he'd carried on @ ~0.4ppg through the whole season, things would look a lot better on the whole. But that was right around where Weber became the hero of the day and the PP time went his way, Vey started shuttling in and out of the lineup as a real "depth guy" and injury replacement, intermittent PP time. Generally relegated to a true "back seat" role.
But he didn't just fall off the face of the earth post-November, or even post-December. His January was right on pace with his season to that point, production-wise.
It was Feb-March-April where things went into a tailspin for him statistically. Coinciding roughly with a reduced role.