Just because he's somewhat gifted offensively doesn't mean he hasn't been catostrophically bad recently, like worse than replacement level junk.
Patrick Wiercioch is sadly of the better offensive defenders on the team right now, and he hasn't sniffed any NHL action. When Kris Letang went down last year, Pittsburgh chose to keep Pouliot out of the lineup for a reasons we have seen why recently, guys has been junk, imagine if Pittsburgh deployed him in the finals against Nashville, we might have seen a repeat of the -5 game he had against them last week.